diff --git a/api.planx.uk/lib/notify/index.ts b/api.planx.uk/lib/notify/index.ts
index a3963d4d9d..7970f70cc3 100644
--- a/api.planx.uk/lib/notify/index.ts
+++ b/api.planx.uk/lib/notify/index.ts
@@ -66,7 +66,7 @@ const sendEmail = async (
       expiryDate?: string;
     } = { message: "Success" };
     if (template === "expiry")
-      softDeleteSession(config.personalisation.sessionId!);
+      await softDeleteSession(config.personalisation.sessionId!);
     if (template === "save")
       returnValue.expiryDate = config.personalisation.expiryDate;
     return returnValue;
diff --git a/api.planx.uk/modules/admin/session/bops.test.ts b/api.planx.uk/modules/admin/session/bops.test.ts
index f4441e20dc..245ae59063 100644
--- a/api.planx.uk/modules/admin/session/bops.test.ts
+++ b/api.planx.uk/modules/admin/session/bops.test.ts
@@ -37,6 +37,18 @@ describe("BOPS payload admin endpoint", () => {
       .expect(403);
   });
 
+  it("returns an error if the BOPS payload generation fails", async () => {
+    mockGenerateBOPSPayload.mockRejectedValueOnce("Error!");
+
+    await supertest(app)
+      .get(endpoint`123`)
+      .set(authHeader({ role: "platformAdmin" }))
+      .expect(500)
+      .then((res) => {
+        expect(res.body.error).toMatch(/Failed to get BOPS payload/);
+      });
+  });
+
   it("returns a JSON payload", async () => {
     await supertest(app)
       .get(endpoint`123`)
diff --git a/api.planx.uk/modules/admin/session/digitalPlanningData.test.ts b/api.planx.uk/modules/admin/session/digitalPlanningData.test.ts
index 09d3f114c9..9197f45b14 100644
--- a/api.planx.uk/modules/admin/session/digitalPlanningData.test.ts
+++ b/api.planx.uk/modules/admin/session/digitalPlanningData.test.ts
@@ -40,6 +40,22 @@ describe("Digital Planning Application payload admin endpoint", () => {
       .expect(403);
   });
 
+  it("returns an error if the XML generation fails", async () => {
+    mockGenerateDigitalPlanningApplicationPayload.mockRejectedValueOnce(
+      "Error!",
+    );
+
+    await supertest(app)
+      .get(endpoint`123`)
+      .set(authHeader({ role: "platformAdmin" }))
+      .expect(500)
+      .then((res) => {
+        expect(res.body.error).toMatch(
+          /Failed to make Digital Planning Application payload/,
+        );
+      });
+  });
+
   it("returns a valid JSON payload", async () => {
     await supertest(app)
       .get(endpoint`123`)
diff --git a/api.planx.uk/modules/admin/session/oneAppXML.test.ts b/api.planx.uk/modules/admin/session/oneAppXML.test.ts
index 5988ba1778..af18f0d186 100644
--- a/api.planx.uk/modules/admin/session/oneAppXML.test.ts
+++ b/api.planx.uk/modules/admin/session/oneAppXML.test.ts
@@ -38,6 +38,18 @@ describe("OneApp XML endpoint", () => {
       .expect(403);
   });
 
+  it("returns an error if the XML generation fails", async () => {
+    mockGenerateOneAppXML.mockRejectedValueOnce("Error!");
+
+    await supertest(app)
+      .get(endpoint`123`)
+      .set(authHeader({ role: "platformAdmin" }))
+      .expect(500)
+      .then((res) => {
+        expect(res.body.error).toMatch(/Failed to get OneApp XML/);
+      });
+  });
+
   it("returns XML", async () => {
     await supertest(app)
       .get(endpoint`123`)
diff --git a/api.planx.uk/modules/admin/session/summary.test.ts b/api.planx.uk/modules/admin/session/summary.test.ts
index a74cbd9844..75551c8cac 100644
--- a/api.planx.uk/modules/admin/session/summary.test.ts
+++ b/api.planx.uk/modules/admin/session/summary.test.ts
@@ -39,6 +39,10 @@ describe("Session summary admin endpoint", () => {
       .expect(403);
   });
 
+  it.todo("returns an error if the service fails");
+
+  it.todo("returns an error if the session can't be found");
+
   it("returns JSON", async () => {
     await supertest(app)
       .get(endpoint`abc123`)
diff --git a/api.planx.uk/modules/admin/session/zip.test.ts b/api.planx.uk/modules/admin/session/zip.test.ts
index dccf00e126..0444e5734a 100644
--- a/api.planx.uk/modules/admin/session/zip.test.ts
+++ b/api.planx.uk/modules/admin/session/zip.test.ts
@@ -40,4 +40,6 @@ describe("zip data admin endpoint", () => {
       .expect(200)
       .expect("content-type", "application/zip");
   });
+
+  it.todo("returns an error if the service fails");
 });
diff --git a/api.planx.uk/modules/pay/service/inviteToPay/sendPaymentEmail.test.ts b/api.planx.uk/modules/pay/service/inviteToPay/sendPaymentEmail.test.ts
index cc2c593d67..d836ff4c21 100644
--- a/api.planx.uk/modules/pay/service/inviteToPay/sendPaymentEmail.test.ts
+++ b/api.planx.uk/modules/pay/service/inviteToPay/sendPaymentEmail.test.ts
@@ -133,9 +133,14 @@ describe("Send email endpoint for invite to pay templates", () => {
   });
 
   describe("'Payment Expiry' templates", () => {
-    const _templates = ["payment-expiry", "payment-expiry-agent"];
-    it.todo(
-      "soft deletes the payment_request when a payment expiry email is sent",
-    );
+    const templates = ["payment-expiry", "payment-expiry-agent"];
+
+    for (const template of templates) {
+      describe(`${template} Template`, () => {
+        it.todo(
+          "soft deletes the payment_request when a payment expiry email is sent",
+        );
+      });
+    }
   });
 });
diff --git a/api.planx.uk/modules/pay/service/inviteToPay/sendPaymentEmail.ts b/api.planx.uk/modules/pay/service/inviteToPay/sendPaymentEmail.ts
index c23a806896..7f0899a204 100644
--- a/api.planx.uk/modules/pay/service/inviteToPay/sendPaymentEmail.ts
+++ b/api.planx.uk/modules/pay/service/inviteToPay/sendPaymentEmail.ts
@@ -38,8 +38,6 @@ const sendSinglePaymentEmail = async ({
       paymentRequestId,
       template,
     );
-    if (!session || !paymentRequest)
-      throw Error(`Invalid payment request: ${paymentRequestId}`);
     const config = await getInviteToPayNotifyConfig(session, paymentRequest);
     const recipient = template.includes("-agent")
       ? session.email
diff --git a/api.planx.uk/modules/saveAndReturn/service/utils.test.ts b/api.planx.uk/modules/saveAndReturn/service/utils.test.ts
index 2d12b1e69a..d272205f34 100644
--- a/api.planx.uk/modules/saveAndReturn/service/utils.test.ts
+++ b/api.planx.uk/modules/saveAndReturn/service/utils.test.ts
@@ -1,5 +1,11 @@
-import { Team } from "../../../types";
-import { convertSlugToName, getResumeLink } from "./utils";
+import { queryMock } from "../../../tests/graphqlQueryMock";
+import { LowCalSession, LowCalSessionData, Team } from "../../../types";
+import {
+  convertSlugToName,
+  getResumeLink,
+  getSessionDetails,
+  setupEmailEventTriggers,
+} from "./utils";
 
 describe("convertSlugToName util function", () => {
   it("should return the correct value", () => {
@@ -41,3 +47,66 @@ describe("getResumeLink util function", () => {
     expect(testCase).toEqual(expectedResult);
   });
 });
+
+describe("getSessionDetails() util function", () => {
+  it("sets defaults for values not in the session", async () => {
+    const result = await getSessionDetails({
+      data: { id: "flowId", passport: { data: {} }, breadcrumbs: {} },
+      id: "abc123",
+      created_at: "2023-01-01",
+      submitted_at: "2023-02-02",
+      has_user_saved: true,
+    } as LowCalSession);
+
+    expect(result.address).toEqual("Address not submitted");
+    expect(result.projectType).toEqual("Project type not submitted");
+  });
+
+  it("defaults to address title if no single line address is present", async () => {
+    const sessionData: LowCalSessionData = {
+      id: "flowId",
+      passport: {
+        data: {
+          _address: {
+            title: "Address title",
+          },
+        },
+      },
+      breadcrumbs: {},
+    };
+
+    const result = await getSessionDetails({
+      data: sessionData,
+      id: "abc123",
+      created_at: "2023-01-01",
+      submitted_at: "2023-02-02",
+      has_user_saved: true,
+    } as LowCalSession);
+
+    expect(result.address).toEqual("Address title");
+  });
+});
+
+describe("setupEmailEventTriggers util function", () => {
+  it("handles GraphQL errors", async () => {
+    queryMock.mockQuery({
+      name: "SetupEmailNotifications",
+      data: {
+        session: {
+          id: "123",
+          hasUserSaved: true,
+        },
+      },
+      variables: {
+        sessionId: "123",
+      },
+      graphqlErrors: [
+        {
+          message: "Something went wrong",
+        },
+      ],
+    });
+
+    await expect(setupEmailEventTriggers("123")).rejects.toThrow();
+  });
+});
diff --git a/api.planx.uk/modules/saveAndReturn/service/utils.ts b/api.planx.uk/modules/saveAndReturn/service/utils.ts
index a46968a7b0..b1b26b5f38 100644
--- a/api.planx.uk/modules/saveAndReturn/service/utils.ts
+++ b/api.planx.uk/modules/saveAndReturn/service/utils.ts
@@ -147,7 +147,7 @@ interface SessionDetails {
 /**
  * Parse session details into an object which will be read by email template
  */
-const getSessionDetails = async (
+export const getSessionDetails = async (
   session: LowCalSession,
 ): Promise<SessionDetails> => {
   const passportProtectTypes =
@@ -248,7 +248,7 @@ interface SetupEmailNotifications {
 // Update lowcal_sessions.has_user_saved column to kick-off the setup_lowcal_expiry_events &
 // setup_lowcal_reminder_events event triggers in Hasura
 // Should only run once on initial save of a session
-const setupEmailEventTriggers = async (sessionId: string) => {
+export const setupEmailEventTriggers = async (sessionId: string) => {
   try {
     const mutation = gql`
       mutation SetupEmailNotifications($sessionId: uuid!) {
diff --git a/api.planx.uk/modules/sendEmail/index.test.ts b/api.planx.uk/modules/sendEmail/index.test.ts
index 96debfbfcc..8ae931321a 100644
--- a/api.planx.uk/modules/sendEmail/index.test.ts
+++ b/api.planx.uk/modules/sendEmail/index.test.ts
@@ -7,6 +7,7 @@ import {
   mockSetupEmailNotifications,
   mockSoftDeleteLowcalSession,
   mockValidateSingleSessionRequest,
+  mockValidateSingleSessionRequestMissingSession,
 } from "../../tests/mocks/saveAndReturnMocks";
 import { CoreDomainClient } from "@opensystemslab/planx-core";
 
@@ -200,6 +201,71 @@ describe("Send Email endpoint", () => {
   });
 
   describe("'Expiry' template", () => {
+    it("returns an error if unable to delete the session", async () => {
+      queryMock.mockQuery({
+        name: "ValidateSingleSessionRequest",
+        data: {
+          flows_by_pk: mockFlow,
+          lowcalSessions: [
+            {
+              ...mockLowcalSession,
+              id: "456",
+            },
+          ],
+        },
+        variables: {
+          sessionId: "456",
+        },
+      });
+
+      queryMock.mockQuery({
+        name: "SetupEmailNotifications",
+        data: {
+          session: {
+            id: "456",
+            hasUserSaved: true,
+          },
+        },
+        variables: {
+          sessionId: "456",
+        },
+      });
+
+      queryMock.mockQuery({
+        name: "SoftDeleteLowcalSession",
+        data: {
+          update_lowcal_sessions_by_pk: {
+            id: "456",
+          },
+        },
+        variables: {
+          sessionId: "456",
+        },
+        matchOnVariables: true,
+        graphqlErrors: [
+          {
+            message: "Something went wrong",
+          },
+        ],
+      });
+
+      const data = {
+        payload: {
+          sessionId: "456",
+          email: TEST_EMAIL,
+        },
+      };
+
+      await supertest(app)
+        .post(`/send-email/expiry`)
+        .set("Authorization", "testtesttest")
+        .send(data)
+        .expect(500)
+        .then((res) => {
+          expect(res.body.error).toMatch(/Error deleting session/);
+        });
+    });
+
     it("soft deletes the session when an expiry email is sent", async () => {
       const data = {
         payload: {
@@ -239,6 +305,18 @@ describe("Setting up send email events", () => {
     queryMock.mockQuery(mockSetupEmailNotifications);
   });
 
+  test("Missing sessions are handled", async () => {
+    queryMock.mockQuery(mockValidateSingleSessionRequestMissingSession);
+
+    await supertest(app)
+      .post(SAVE_ENDPOINT)
+      .send(data)
+      .expect(500)
+      .then((res) => {
+        expect(res.body.error).toMatch(/Unable to find session/);
+      });
+  });
+
   test("Initial save sets ups email notifications", async () => {
     queryMock.mockQuery(mockValidateSingleSessionRequest);
 
diff --git a/api.planx.uk/tests/mocks/saveAndReturnMocks.ts b/api.planx.uk/tests/mocks/saveAndReturnMocks.ts
index ec75fae2d2..199acc438a 100644
--- a/api.planx.uk/tests/mocks/saveAndReturnMocks.ts
+++ b/api.planx.uk/tests/mocks/saveAndReturnMocks.ts
@@ -174,6 +174,18 @@ export const mockValidateSingleSessionRequest = {
   variables: {
     sessionId: mockLowcalSession.id,
   },
+  matchOnVariables: true,
+};
+
+export const mockValidateSingleSessionRequestMissingSession = {
+  name: "ValidateSingleSessionRequest",
+  data: {
+    flows_by_pk: mockFlow,
+    lowcalSessions: [],
+  },
+  variables: {
+    sessionId: mockLowcalSession.id,
+  },
 };
 
 export const mockSoftDeleteLowcalSession = {
@@ -186,6 +198,7 @@ export const mockSoftDeleteLowcalSession = {
   variables: {
     sessionId: "123",
   },
+  matchOnVariables: true,
 };
 
 export const mockSetupEmailNotifications = {