diff --git a/app/main/forms.py b/app/main/forms.py
index 007393b9a..1a904a420 100644
--- a/app/main/forms.py
+++ b/app/main/forms.py
@@ -2196,11 +2196,11 @@ class ChooseBrandingForm(StripWhitespaceForm):
         if self.something_else_is_only_option:
             self.options.data = self.FALLBACK_OPTION_VALUE
 
-    @staticmethod
-    def get_available_choices(service, branding_type):
+    @classmethod
+    def get_available_choices(cls, service, branding_type):
         return (
             list(branding.get_available_choices(service, branding_type)) +
-            [ChooseBrandingForm.FALLBACK_OPTION]
+            [cls.FALLBACK_OPTION]
         )
 
     @property
@@ -2221,12 +2221,12 @@ class ChooseBrandingForm(StripWhitespaceForm):
 
 class ChooseEmailBrandingForm(ChooseBrandingForm):
     def __init__(self, service_id):
-        ChooseBrandingForm.__init__(self, service_id, branding_type='email')
+        super().__init__(service_id, branding_type='email')
 
 
 class ChooseLetterBrandingForm(ChooseBrandingForm):
     def __init__(self, service_id):
-        ChooseBrandingForm.__init__(self, service_id, branding_type='letter')
+        super().__init__(service_id, branding_type='letter')
 
 
 class SomethingElseBrandingForm(StripWhitespaceForm):
diff --git a/tests/app/utils/test_branding.py b/tests/app/utils/test_branding.py
index da048e04a..b42a9da76 100644
--- a/tests/app/utils/test_branding.py
+++ b/tests/app/utils/test_branding.py
@@ -8,20 +8,19 @@ from tests import organisation_json
 
 
 @pytest.mark.parametrize('branding_type', ['email', 'letter'])
-@pytest.mark.parametrize('org_type, existing_branding, expected_options', [
-    ('central', None, []),
-    ('local', None, []),
-    ('nhs_central', None, [('nhs', 'NHS')]),
-    ('nhs_local', None, [('nhs', 'NHS')]),
-    ('nhs_gp', None, [('nhs', 'NHS')]),
-    ('emergency_service', None, []),
-    ('other', None, []),
+@pytest.mark.parametrize('org_type, expected_options', [
+    ('central', []),
+    ('local', []),
+    ('nhs_central', [('nhs', 'NHS')]),
+    ('nhs_local', [('nhs', 'NHS')]),
+    ('nhs_gp', [('nhs', 'NHS')]),
+    ('emergency_service', []),
+    ('other', []),
 ])
-def test_get_available_choices_no_org(
+def test_get_available_choices_service_not_assigned_to_org(
     service_one,
     branding_type,
     org_type,
-    existing_branding,
     expected_options,
 ):
     service_one['organisation_type'] = org_type
@@ -32,20 +31,19 @@ def test_get_available_choices_no_org(
 
 
 @pytest.mark.parametrize('branding_type', ['email', 'letter'])
-@pytest.mark.parametrize('org_type, existing_branding, expected_options', [
-    ('local', None, [('organisation', 'Test Organisation')]),
-    ('nhs_central', None, [('nhs', 'NHS')]),
-    ('nhs_local', None, [('nhs', 'NHS')]),
-    ('nhs_gp', None, [('nhs', 'NHS')]),
-    ('emergency_service', None, [('organisation', 'Test Organisation')]),
-    ('other', None, [('organisation', 'Test Organisation')]),
+@pytest.mark.parametrize('org_type, expected_options', [
+    ('local', [('organisation', 'Test Organisation')]),
+    ('nhs_central', [('nhs', 'NHS')]),
+    ('nhs_local', [('nhs', 'NHS')]),
+    ('nhs_gp', [('nhs', 'NHS')]),
+    ('emergency_service', [('organisation', 'Test Organisation')]),
+    ('other', [('organisation', 'Test Organisation')]),
 ])
-def test_get_available_choices_with_org(
+def test_get_available_choices_service_assigned_to_org(
     mocker,
     service_one,
     branding_type,
     org_type,
-    existing_branding,
     expected_options,
     mock_get_service_organisation,
 ):
@@ -125,6 +123,11 @@ def test_get_available_choices_letter_branding_set(
         'app.organisations_client.get_organisation',
         return_value=organisation_json()
     )
+    mocker.patch(
+        'app.models.service.Service.letter_branding_id',
+        new_callable=PropertyMock,
+        return_value='1234-abcd',
+    )
 
     options = get_available_choices(service, branding_type='letter')
     assert list(options) == [