diff --git a/lib/model_patches.rb b/lib/model_patches.rb
index 7896b366..1c5fa956 100644
--- a/lib/model_patches.rb
+++ b/lib/model_patches.rb
@@ -73,7 +73,7 @@ def late_calculator
     prepend ProAccountBans::ModelMethods
   end
 
-  PublicBody.excluded_calculated_home_page_domains << %w[
+  PublicBody.excluded_calculated_home_page_domains += %w[
     aol.co.uk
     blueyonder.co.uk
     btconnect.com
diff --git a/spec/public_body_spec.rb b/spec/public_body_spec.rb
new file mode 100644
index 00000000..0fe74519
--- /dev/null
+++ b/spec/public_body_spec.rb
@@ -0,0 +1,15 @@
+require_relative 'spec_helper'
+
+RSpec.describe PublicBody do
+  describe '.excluded_calculated_home_page_domains' do
+    subject { described_class.excluded_calculated_home_page_domains }
+
+    it 'includes default global domains' do
+      is_expected.to include('aol.com')
+    end
+
+    it 'includes expected localise domains' do
+      is_expected.to include('aol.co.uk')
+    end
+  end
+end