diff --git a/lib/st/api/lims.pm b/lib/st/api/lims.pm
index 08713f95..e8367094 100644
--- a/lib/st/api/lims.pm
+++ b/lib/st/api/lims.pm
@@ -897,9 +897,8 @@ sub aggregate_xlanes {
     return;
   }; # End of test function
 
-  my %init = %{$self->_driver_arguments()};
-  $init{'driver_type'} = $self->driver_type;
-  delete $init{'id_run'};
+  my $init = $self->copy_init_args();
+  delete $init->{'id_run'};
 
   my $lims4compisitions = {};
   my @test_attrs = qw/sample_id library_id/;
@@ -908,7 +907,7 @@ sub aggregate_xlanes {
 
   if (!@pools) {
     $can_merge->(\@lanes, @test_attrs); # Test consistency
-    push @aggregated, __PACKAGE__->new(%init, rpt_list => $lanes_rpt_list);
+    push @aggregated, __PACKAGE__->new(%{$init}, rpt_list => $lanes_rpt_list);
   } else {
     my @sizes = uniq (map { $_->num_children } @lanes);
     if (@sizes != 1) { # Test consistency
@@ -925,11 +924,11 @@ sub aggregate_xlanes {
     my $ea = each_arrayref map { [$_->children()] } @lanes;
     while ( my @plexes = $ea->() ) {
       $can_merge->(\@plexes, @test_attrs, 'tag_index');  # Test consistency
-      push @aggregated, __PACKAGE__->new(%init,
+      push @aggregated, __PACKAGE__->new(%{$init},
         rpt_list => npg_tracking::glossary::rpt->deflate_rpts(\@plexes));
     }
     # Add object for tag zero
-    push @aggregated, __PACKAGE__->new(%init,
+    push @aggregated, __PACKAGE__->new(%{$init},
       rpt_list => npg_tracking::glossary::rpt->tag_zero_rpt_list($lanes_rpt_list));
   }
 
diff --git a/t/40-st-lims-merge.t b/t/40-st-lims-merge.t
index d4d7a125..4fd4aa7c 100644
--- a/t/40-st-lims-merge.t
+++ b/t/40-st-lims-merge.t
@@ -130,9 +130,10 @@ subtest 'Create tag zero object' => sub {
 };
 
 subtest 'Aggregation across lanes for pools' => sub {
-  plan tests => 82;
+  plan tests => 89;
   
-  local $ENV{NPG_CACHED_SAMPLESHEET_FILE} = 't/data/test40_lims/samplesheet_novaseq4lanes.csv';
+  local $ENV{NPG_CACHED_SAMPLESHEET_FILE} =
+    't/data/test40_lims/samplesheet_novaseq4lanes.csv';
 
   my $l = st::api::lims->new(rpt_list => '25846:1:3');
   throws_ok { $l->aggregate_xlanes() } qr/Not run-level object/,
@@ -235,6 +236,35 @@ subtest 'Aggregation across lanes for pools' => sub {
     'sample names including spiked phix');
   is (join(q[:], $tag_zero->sample_names(1)), join(q[:], @sample_names),
     'sample names including spiked phix');
+
+  local $ENV{NPG_CACHED_SAMPLESHEET_FILE} = q[];
+  
+  my $id_run = 47995;
+  $l = st::api::lims->new(
+    id_run           => $id_run,
+    id_flowcell_lims => 98292,
+    driver_type      => 'ml_warehouse',
+    mlwh_schema      => $schema_wh,
+  );
+  
+  @merged = $l->aggregate_xlanes(qw/1 2/);
+  is (scalar @merged, 19, 'number of aggregates is number of tags plus two');
+  $tag_zero = pop @merged;
+  $tag_spiked = pop @merged;
+  $tag_last = pop @merged;
+  $tag_first = shift @merged;
+  is ($tag_zero->rpt_list, "$id_run:1:0;$id_run:2:0",
+    'rpt list for tag zero object');
+  my @tag_zero_sample_names = $tag_zero->sample_names();
+  is (@tag_zero_sample_names, 18, '18 sample names are retrieved');
+  is ($tag_zero_sample_names[0], '6751STDY13219539',
+    'first sample name is correct');
+  is ($tag_spiked->rpt_list, "$id_run:1:888;$id_run:2:888",
+    'rpt list for spiked in tag object');
+  is ($tag_last->rpt_list, "$id_run:1:17;$id_run:2:17",
+    'rpt list for tag 21 object');
+  is ($tag_first->rpt_list, "$id_run:1:1;$id_run:2:1",
+    'rpt list for tag 1 object');
 };
 
 subtest 'Aggregation across lanes for non-pools' => sub {