diff --git a/tests/__init__.py b/tests/__init__.py
index c65fb0996..458873f55 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -214,6 +214,7 @@ def template_json(service_id,
                   reply_to=None,
                   reply_to_text=None,
                   is_precompiled_letter=False,
+                  postage=None
                   ):
     template = {
         'id': id_,
@@ -230,6 +231,7 @@ def template_json(service_id,
         'reply_to_text': reply_to_text,
         'is_precompiled_letter': is_precompiled_letter,
         'folder': None,
+        'postage': postage
     }
     if content is None:
         template['content'] = "template content"
diff --git a/tests/app/main/views/test_templates.py b/tests/app/main/views/test_templates.py
index 09dee0ec0..6b438b568 100644
--- a/tests/app/main/views/test_templates.py
+++ b/tests/app/main/views/test_templates.py
@@ -915,7 +915,7 @@ def test_should_redirect_when_saving_a_template(
     assert response.location == url_for(
         '.view_template', service_id=service['id'], template_id=template_id, _external=True)
     mock_update_service_template.assert_called_with(
-        template_id, name, 'sms', content, service['id'], None, 'normal')
+        template_id, name, 'sms', content, service['id'], None, 'normal', postage=None)
 
 
 def test_should_edit_content_when_process_type_is_priority_not_platform_admin(
@@ -951,7 +951,8 @@ def test_should_edit_content_when_process_type_is_priority_not_platform_admin(
         "new template <em>content</em> with & entity",
         service['id'],
         None,
-        'priority'
+        'priority',
+        postage=None
     )
 
 
@@ -1037,9 +1038,10 @@ def test_should_403_when_create_template_with_process_type_of_priority_for_non_p
     mock_update_service_template.called == 0
 
 
-@pytest.mark.parametrize('template_mock, expected_paragraphs', [
+@pytest.mark.parametrize('template_mock, template_type, expected_paragraphs', [
     (
         mock_get_service_email_template,
+        "email",
         [
             'You removed ((date))',
             'You added ((name))',
@@ -1048,6 +1050,7 @@ def test_should_403_when_create_template_with_process_type_of_priority_for_non_p
     ),
     (
         mock_get_service_letter_template,
+        "letter",
         [
             'You removed ((date))',
             'You added ((name))',
@@ -1067,6 +1070,7 @@ def test_should_show_interstitial_when_making_breaking_change(
     fake_uuid,
     mocker,
     template_mock,
+    template_type,
     expected_paragraphs,
 ):
     template_mock(
@@ -1076,17 +1080,22 @@ def test_should_show_interstitial_when_making_breaking_change(
     )
     service_id = fake_uuid
     template_id = fake_uuid
+    data = {
+        'id': template_id,
+        'name': "new name",
+        'template_content': "hello lets talk about ((thing))",
+        'template_type': template_type,
+        'subject': 'reminder \'" <span> & ((name))',
+        'service': service_id,
+        'process_type': 'normal'
+    }
+
+    if template_type == "letter":
+        data.update({"postage": "service_default"})
+
     response = logged_in_client.post(
         url_for('.edit_service_template', service_id=service_id, template_id=template_id),
-        data={
-            'id': template_id,
-            'name': "new name",
-            'template_content': "hello lets talk about ((thing))",
-            'template_type': 'email',
-            'subject': 'reminder \'" <span> & ((name))',
-            'service': service_id,
-            'process_type': 'normal'
-        }
+        data=data
     )
 
     assert response.status_code == 200
@@ -1232,7 +1241,7 @@ def test_should_redirect_when_saving_a_template_email(
         template_id=template_id,
         _external=True)
     mock_update_service_template.assert_called_with(
-        template_id, name, 'email', content, service_id, subject, 'normal')
+        template_id, name, 'email', content, service_id, subject, 'normal', postage=None)
 
 
 def test_should_show_delete_template_page_with_time_block(
diff --git a/tests/conftest.py b/tests/conftest.py
index 282cd22f2..931a7bc69 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -881,7 +881,7 @@ def mock_get_service_email_template_without_placeholders(mocker):
 
 @pytest.fixture(scope='function')
 def mock_get_service_letter_template(mocker, content=None, subject=None):
-    def _get(service_id, template_id, version=None):
+    def _get(service_id, template_id, version=None, postage=None):
         template = template_json(
             service_id,
             template_id,
@@ -889,6 +889,7 @@ def mock_get_service_letter_template(mocker, content=None, subject=None):
             "letter",
             content or "Template <em>content</em> with & entity",
             subject or "Subject",
+            postage=postage,
         )
         return {'data': template}
 
@@ -910,8 +911,8 @@ def mock_create_service_template(mocker, fake_uuid):
 
 @pytest.fixture(scope='function')
 def mock_update_service_template(mocker):
-    def _update(id_, name, type_, content, service, subject=None, process_type=None):
-        template = template_json(service, id_, name, type_, content, subject, process_type)
+    def _update(id_, name, type_, content, service, subject=None, process_type=None, postage=None):
+        template = template_json(service, id_, name, type_, content, subject, process_type, postage)
         return {'data': template}
 
     return mocker.patch(
@@ -939,7 +940,7 @@ def mock_create_service_template_content_too_big(mocker):
 
 @pytest.fixture(scope='function')
 def mock_update_service_template_400_content_too_big(mocker):
-    def _update(id_, name, type_, content, service, subject=None, process_type=None):
+    def _update(id_, name, type_, content, service, subject=None, process_type=None, postage=None):
         json_mock = Mock(return_value={
             'message': {'content': ["Content has a character count greater than the limit of 459"]},
             'result': 'error'