diff --git a/code/CMSProfileController.php b/code/CMSProfileController.php
index d271804d1..8ef85ae74 100644
--- a/code/CMSProfileController.php
+++ b/code/CMSProfileController.php
@@ -2,17 +2,13 @@
 
 namespace SilverStripe\Admin;
 
-use SilverStripe\CMS\Controllers\CMSMain;
 use SilverStripe\Control\HTTPResponse;
 use SilverStripe\Forms\Form;
 use SilverStripe\Forms\HiddenField;
-use SilverStripe\Forms\FormAction;
-use SilverStripe\Model\List\ArrayList;
 use SilverStripe\Security\Member;
-use SilverStripe\Security\Permission;
 use SilverStripe\Security\Security;
 
-class CMSProfileController extends LeftAndMain
+class CMSProfileController extends SingleRecordAdmin
 {
     private static $url_segment = 'myprofile';
 
@@ -20,98 +16,61 @@ class CMSProfileController extends LeftAndMain
 
     private static $required_permission_codes = 'CMS_ACCESS';
 
-    /**
-     * @deprecated 5.4.0 Will be renamed to model_class
-     */
-    private static $tree_class = Member::class;
+    private static $model_class = Member::class;
 
     private static $ignore_menuitem = true;
 
-    public function getEditForm($id = null, $fields = null)
-    {
-        $this->setCurrentPageID(Security::getCurrentUser()->ID);
-
-        $form = parent::getEditForm($id, $fields);
+    private static bool $restrict_to_single_record = false;
 
-        if ($form instanceof HTTPResponse) {
-            return $form;
-        }
+    private static bool $allow_new_record = false;
 
-        $form->Fields()->removeByName('LastVisited');
-        $form->Fields()->push(new HiddenField('ID', null, Security::getCurrentUser()->ID));
-        $form->Actions()->push(
-            FormAction::create('save', _t(CMSMain::class . '.SAVE', 'Save'))
-                ->addExtraClass('btn-primary font-icon-save')
-                ->setUseButtonTag(true)
-        );
-
-        $form->Actions()->removeByName('action_delete');
-
-        if ($member = Security::getCurrentUser()) {
-            $form->setValidator($member->getValidator());
-        } else {
-            $form->setValidator(Member::singleton()->getValidator());
-        }
-
-        if ($form->Fields()->hasTabSet()) {
-            $form->Fields()->findOrMakeTab('Root')->setTemplate('SilverStripe\\Forms\\CMSTabSet');
+    protected function init()
+    {
+        parent::init();
+        if (!$this->getResponse()->isRedirect()) {
+            $this->setCurrentPageID(Security::getCurrentUser()->ID);
         }
+    }
 
-        $form->addExtraClass('member-profile-form root-form cms-edit-form center fill-height');
-
+    public function getEditForm($id = null, $fields = null): Form
+    {
+        $form = parent::getEditForm($id, $fields);
+        $form->Fields()->push(HiddenField::create('ID', null, Security::getCurrentUser()->ID));
         return $form;
     }
 
     public function canView($member = null)
     {
         $currentUser = Security::getCurrentUser();
-
         if (!$member && $member !== false) {
             $member = $currentUser;
         }
-
-        // cms menus only for logged-in members
+        // cms menus are only for logged-in members
         if (!$member) {
             return false;
         }
-
         // Check they are trying to edit themselves and they have permissions
         return $member->ID === $currentUser->ID && parent::canView($member);
     }
 
     public function save(array $data, Form $form): HTTPResponse
     {
-        $member = Member::get()->byID($data['ID']);
-        if (!$member) {
-            $this->httpError(404);
-        }
-        $origLocale = $member->Locale;
-
-        if (!$member->canEdit()) {
-            $form->sessionMessage(_t(__CLASS__.'.CANTEDIT', 'You don\'t have permission to do that'), 'bad');
-            return $this->redirectBack();
+        // Make sure the ID is a positive number
+        $id = $data['ID'] ?? null;
+        if ((!is_int($id) && !ctype_digit($id)) || $id < 1) {
+            $this->httpError(400);
         }
-
+        // Get the current member locale so we can see if it changes
+        $member = Member::get()->byID($id);
+        $origLocale = $member?->Locale;
+        // actual save (along with error handling e.g. if there's no member with that ID) is handled by the parent class
         $response = parent::save($data, $form);
-
+        // If the member locale changes, reload the full CMS so localisation can kick in.
+        // Otherwise only the edit form will reload.
         if (isset($data['Locale']) && $origLocale != $data['Locale']) {
             $response->addHeader('X-Reload', true);
             $response->addHeader('X-ControllerURL', $this->Link());
         }
-
         return $response;
     }
-
-    /**
-     * Only show first element, as the profile form is limited to editing
-     * the current member it doesn't make much sense to show the member name
-     * in the breadcrumbs.
-     *
-     * @param bool $unlinked
-     */
-    public function Breadcrumbs($unlinked = false)
-    {
-        $items = parent::Breadcrumbs($unlinked);
-        return new ArrayList([$items[0]]);
-    }
 }
diff --git a/code/LeftAndMain.php b/code/LeftAndMain.php
index 76d5558aa..bba5a92a5 100644
--- a/code/LeftAndMain.php
+++ b/code/LeftAndMain.php
@@ -100,7 +100,7 @@ class LeftAndMain extends AdminController implements PermissionProvider
      * @var string
      * @deprecated 5.4.0 Will be renamed to model_class
      */
-    private static $tree_class = null;
+    private static $model_class = null;
 
     /**
      * @var array
@@ -939,7 +939,7 @@ public function PreviewPanel()
      */
     public function getRecord($id)
     {
-        $className = $this->config()->get('tree_class');
+        $className = $this->config()->get('model_class');
         if (!$className) {
             return null;
         }
@@ -1005,7 +1005,7 @@ protected function getSearchFilter()
     public function save(array $data, Form $form): HTTPResponse
     {
         $request = $this->getRequest();
-        $className = $this->config()->get('tree_class');
+        $className = $this->config()->get('model_class');
 
         // Existing or new record?
         $id = $data['ID'];
@@ -1018,7 +1018,7 @@ public function save(array $data, Form $form): HTTPResponse
                 $this->httpError(404, "Bad record ID #" . (int)$id);
             }
         } else {
-            if (!singleton($this->config()->get('tree_class'))->canCreate()) {
+            if (!singleton($this->config()->get('model_class'))->canCreate()) {
                 return Security::permissionFailure($this);
             }
             $record = $this->getNewItem($id, false);
@@ -1054,7 +1054,7 @@ public function save(array $data, Form $form): HTTPResponse
      */
     public function getNewItem($id, $setID = true)
     {
-        $class = $this->config()->get('tree_class');
+        $class = $this->config()->get('model_class');
         $object = Injector::inst()->create($class);
         if ($setID) {
             $object->ID = $id;
@@ -1064,7 +1064,7 @@ public function getNewItem($id, $setID = true)
 
     public function delete(array $data, Form $form): HTTPResponse
     {
-        $className = $this->config()->get('tree_class');
+        $className = $this->config()->get('model_class');
 
         $id = $data['ID'];
         $record = DataObject::get_by_id($className, $id);
@@ -1096,7 +1096,7 @@ public function delete(array $data, Form $form): HTTPResponse
      * method in an entwine subclass. This method can accept a record identifier,
      * selected either in custom logic, or through {@link currentPageID()}.
      * The form usually construct itself from {@link DataObject->getCMSFields()}
-     * for the specific managed subclass defined in {@link LeftAndMain::$tree_class}.
+     * for the specific managed subclass defined in {@link LeftAndMain::$model_class}.
      *
      * @param HTTPRequest $request Passed if executing a HTTPRequest directly on the form.
      * If empty, this is invoked as $EditForm in the template
@@ -1149,8 +1149,8 @@ public function getEditForm($id = null, $fields = null)
             $fields->push(new HiddenField('ClassName'));
         }
 
-        $tree_class = $this->config()->get('tree_class');
-        if ($tree_class::has_extension(Hierarchy::class)
+        $modelClass = $this->config()->get('model_class');
+        if ($modelClass::has_extension(Hierarchy::class)
             && !$fields->dataFieldByName('ParentID')
         ) {
             $fields->push(new HiddenField('ParentID'));
@@ -1171,14 +1171,14 @@ public function getEditForm($id = null, $fields = null)
             if (!$actions || !$actions->count()) {
                 if ($record->hasMethod('canEdit') && $record->canEdit()) {
                     $actions->push(
-                        FormAction::create('save', _t(CMSMain::class . '.SAVE', 'Save'))
+                        FormAction::create('save', _t(__CLASS__ . '.SAVE', 'Save'))
                             ->addExtraClass('btn btn-primary')
                             ->addExtraClass('font-icon-add-circle')
                     );
                 }
                 if ($record->hasMethod('canDelete') && $record->canDelete()) {
                     $actions->push(
-                        FormAction::create('delete', _t(ModelAdmin::class . '.DELETE', 'Delete'))
+                        FormAction::create('delete', _t(__CLASS__ . '.DELETE', 'Delete'))
                             ->addExtraClass('btn btn-secondary')
                     );
                 }
@@ -1221,24 +1221,7 @@ public function getEditForm($id = null, $fields = null)
             $form->addExtraClass('cms-previewable');
         }
         $form->addExtraClass('fill-height');
-
-        if ($record->hasMethod('getCMSCompositeValidator')) {
-            // As of framework v4.7, a CompositeValidator is always available form a DataObject, but it may be
-            // empty (which is fine)
-            $form->setValidator($record->getCMSCompositeValidator());
-        } elseif ($record->hasMethod('getCMSValidator')) {
-            // BC support for framework < v4.7
-            $validator = $record->getCMSValidator();
-
-            // The clientside (mainly LeftAndMain*.js) rely on ajax responses
-            // which can be evaluated as javascript, hence we need
-            // to override any global changes to the validation handler.
-            if ($validator) {
-                $form->setValidator($validator);
-            }
-        } else {
-            $form->unsetValidator();
-        }
+        $form->setValidator($record->getCMSCompositeValidator());
 
         // Check if this form is readonly
         if (!$record->canEdit()) {
@@ -1330,7 +1313,7 @@ public function EditFormTools()
      */
     public function batchactions()
     {
-        return new CMSBatchActionHandler($this, 'batchactions', $this->config()->get('tree_class'));
+        return new CMSBatchActionHandler($this, 'batchactions', $this->config()->get('model_class'));
     }
 
     /**
diff --git a/code/SecurityAdmin.php b/code/SecurityAdmin.php
index c17d42ac8..561f282e0 100755
--- a/code/SecurityAdmin.php
+++ b/code/SecurityAdmin.php
@@ -58,10 +58,7 @@ class SecurityAdmin extends ModelAdmin implements PermissionProvider
 
     private static $menu_priority = 0;
 
-    /**
-     * @deprecated 5.4.0 Will be renamed to model_class
-     */
-    private static $tree_class = Group::class;
+    private static $model_class = Group::class;
 
     private static $required_permission_codes = 'CMS_ACCESS_SecurityAdmin';
 
diff --git a/code/SingleRecordAdmin.php b/code/SingleRecordAdmin.php
new file mode 100644
index 000000000..1b816cbc9
--- /dev/null
+++ b/code/SingleRecordAdmin.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace SilverStripe\Admin;
+
+use SilverStripe\Forms\Form;
+use SilverStripe\ORM\DataObject;
+
+/**
+ * The base class for admin sections that exist for editing a single record.
+ */
+abstract class SingleRecordAdmin extends LeftAndMain
+{
+    /**
+     * Determines if there should be a single record in the database that this admin edits.
+     *
+     * If false, you need to provide a mechanism to tell the form which record it should be editing.
+     * This could be an action (e.g. edit/$ID), or could be based on something about the current member, etc.
+     */
+    private static bool $restrict_to_single_record = true;
+
+    /**
+     * If no record exists, allow a new one to be created
+     */
+    private static bool $allow_new_record = true;
+
+    public function getEditForm($id = null, $fields = null): ?Form
+    {
+        $form = parent::getEditForm($id, $fields);
+        // Keep the tabs on the top row, rather than underneath
+        if ($form?->Fields()->hasTabSet()) {
+            $form->Fields()->findOrMakeTab('Root')->setTemplate('SilverStripe/Forms/CMSTabSet');
+        }
+        return $form;
+    }
+
+    public function getRecord($id): ?DataObject
+    {
+        if (!$id) {
+            return $this->getSingleRecord();
+        }
+        return parent::getRecord($id);
+    }
+
+    protected function getSingleRecord(): ?DataObject
+    {
+        $record = null;
+        $modelClass = static::config()->get('model_class');
+        if (static::config()->get('restrict_to_single_record')) {
+            $record = DataObject::get_one($modelClass);
+        }
+        if (!$record && static::config()->get('allow_new_record')) {
+            $record = $modelClass::create();
+        }
+        return $record;
+    }
+}
diff --git a/tests/behat/features/profile.feature b/tests/behat/features/profile.feature
index 77bc78720..b81914004 100644
--- a/tests/behat/features/profile.feature
+++ b/tests/behat/features/profile.feature
@@ -65,3 +65,7 @@ Feature: Manage my own settings
     And I select "German (Germany)" from "Interface Language"
     And I press the "Save" button
     Then I should see "Sprache"
+
+  Scenario: Breadcrumbs are in the correct place
+    Then I should see "Main" in the ".cms-content-header-tabs" element
+    And I should not see "Main" in the "#Form_EditForm" element
diff --git a/tests/php/LeftAndMainTest/MyTreeController.php b/tests/php/LeftAndMainTest/MyTreeController.php
index 711e64976..0e09d1466 100644
--- a/tests/php/LeftAndMainTest/MyTreeController.php
+++ b/tests/php/LeftAndMainTest/MyTreeController.php
@@ -9,7 +9,7 @@ class MyTreeController extends LeftAndMain implements TestOnly
 {
     private static $url_segment = 'mytree/edit';
 
-    private static $tree_class = MyTree::class;
+    private static $model_class = MyTree::class;
 
     private static $allowed_actions = [
         'EditForm'
diff --git a/tests/php/SingleRecordAdminTest.php b/tests/php/SingleRecordAdminTest.php
new file mode 100644
index 000000000..815c3da50
--- /dev/null
+++ b/tests/php/SingleRecordAdminTest.php
@@ -0,0 +1,117 @@
+<?php
+
+namespace SilverStripe\Admin\Tests;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use SilverStripe\Admin\Tests\SingleRecordAdminTest\TestAdmin;
+use SilverStripe\Admin\Tests\SingleRecordAdminTest\TestRecord;
+use SilverStripe\Dev\SapphireTest;
+
+class SingleRecordAdminTest extends SapphireTest
+{
+    protected static $extra_dataobjects = [
+        TestRecord::class,
+    ];
+
+    protected function tearDown(): void
+    {
+        TestRecord::get()->removeAll();
+    }
+
+    public static function provideGetRecord(): array
+    {
+        return [
+            [
+                'recordExists' => false,
+                'restrictToSingleRecord' => false,
+                'allowNew' => false,
+                'useFixtureID' => false,
+                'expected' => null,
+            ],
+            [
+                'recordExists' => false,
+                'restrictToSingleRecord' => false,
+                'allowNew' => false,
+                'useFixtureID' => true,
+                'expected' => null,
+            ],
+            [
+                'recordExists' => true,
+                'restrictToSingleRecord' => false,
+                'allowNew' => false,
+                'useFixtureID' => true,
+                'expected' => 'existing',
+            ],
+            [
+                'recordExists' => true,
+                'restrictToSingleRecord' => false,
+                'allowNew' => false,
+                'useFixtureID' => false,
+                'expected' => null,
+            ],
+            [
+                'recordExists' => true,
+                'restrictToSingleRecord' => true,
+                'allowNew' => false,
+                'useFixtureID' => false,
+                'expected' => 'existing',
+            ],
+            [
+                'recordExists' => true,
+                'restrictToSingleRecord' => false,
+                'allowNew' => true,
+                'useFixtureID' => false,
+                'expected' => 'new',
+            ],
+            [
+                'recordExists' => true,
+                'restrictToSingleRecord' => false,
+                'allowNew' => true,
+                'useFixtureID' => true,
+                'expected' => 'existing',
+            ],
+            [
+                'recordExists' => true,
+                'restrictToSingleRecord' => true,
+                'allowNew' => true,
+                'useFixtureID' => true,
+                'expected' => 'existing',
+            ],
+        ];
+    }
+
+    #[DataProvider('provideGetRecord')]
+    public function testGetRecord(
+        bool $recordExists,
+        bool $restrictToSingleRecord,
+        bool $allowNew,
+        bool $useFixtureID,
+        ?string $expected
+    ): void {
+        $admin = new TestAdmin();
+        if ($recordExists) {
+            $record = new TestRecord();
+            $recordID = $record->write();
+        } else {
+            $recordID = 9999;
+        }
+        TestAdmin::config()->set('restrict_to_single_record', $restrictToSingleRecord);
+        TestAdmin::config()->set('allow_new_record', $allowNew);
+
+        if ($useFixtureID) {
+            $result = $admin->getRecord($recordID);
+        } else {
+            $result = $admin->getRecord(0);
+        }
+
+        if ($expected === 'existing') {
+            $this->assertInstanceOf(TestRecord::class, $result);
+            $this->assertSame($recordID, $result->ID);
+        } elseif ($expected === 'new') {
+            $this->assertInstanceOf(TestRecord::class, $result);
+            $this->assertSame(0, $result->ID);
+        } else {
+            $this->assertNull($result);
+        }
+    }
+}
diff --git a/tests/php/SingleRecordAdminTest/TestAdmin.php b/tests/php/SingleRecordAdminTest/TestAdmin.php
new file mode 100644
index 000000000..d03aa1345
--- /dev/null
+++ b/tests/php/SingleRecordAdminTest/TestAdmin.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace SilverStripe\Admin\Tests\SingleRecordAdminTest;
+
+use SilverStripe\Admin\SingleRecordAdmin;
+use SilverStripe\Dev\TestOnly;
+
+class TestAdmin extends SingleRecordAdmin implements TestOnly
+{
+    private static string $model_class = TestRecord::class;
+}
diff --git a/tests/php/SingleRecordAdminTest/TestRecord.php b/tests/php/SingleRecordAdminTest/TestRecord.php
new file mode 100644
index 000000000..9f6d7040d
--- /dev/null
+++ b/tests/php/SingleRecordAdminTest/TestRecord.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace SilverStripe\Admin\Tests\SingleRecordAdminTest;
+
+use SilverStripe\Dev\TestOnly;
+use SilverStripe\ORM\DataObject;
+
+class TestRecord extends DataObject implements TestOnly
+{
+    // no-op - just need a concrete implementation
+}