diff --git a/app/main/views/service_settings.py b/app/main/views/service_settings.py
index 6278b5818..171bc8cec 100644
--- a/app/main/views/service_settings.py
+++ b/app/main/views/service_settings.py
@@ -73,12 +73,12 @@ def service_settings(service_id):
     reply_to_email_addresses = service_api_client.get_reply_to_email_addresses(service_id)
     reply_to_email_address_count = len(reply_to_email_addresses)
     default_reply_to_email_address = next(
-        (x['email_address'] for x in reply_to_email_addresses if x['is_default']), "None"
+        (x['email_address'] for x in reply_to_email_addresses if x['is_default']), "Not set"
     )
     letter_contact_details = service_api_client.get_letter_contacts(service_id)
     letter_contact_details_count = len(letter_contact_details)
     default_letter_contact_block = next(
-        (Field(x['contact_block'], html='escape') for x in letter_contact_details if x['is_default']), "None"
+        (Field(x['contact_block'], html='escape') for x in letter_contact_details if x['is_default']), "Not set"
     )
     return render_template(
         'views/service-settings.html',
diff --git a/app/templates/components/table.html b/app/templates/components/table.html
index 938f5b040..5fddff5b8 100644
--- a/app/templates/components/table.html
+++ b/app/templates/components/table.html
@@ -92,7 +92,7 @@
   {% endcall %}
 {%- endmacro %}
 
-{% macro optional_text_field(text, default=None) -%}
+{% macro optional_text_field(text, default='Not set') -%}
   {{ text_field(
     text or default,
     status='' if text else 'default'
diff --git a/app/templates/views/service-settings.html b/app/templates/views/service-settings.html
index a94c0e994..6585bd31f 100644
--- a/app/templates/views/service-settings.html
+++ b/app/templates/views/service-settings.html
@@ -135,8 +135,8 @@
         {% if 'letter' in current_service.permissions %}
           {% call row() %}
             {{ text_field('Sender addresses') }}
-            {% call field(status='default' if default_letter_contact_block == "None" else '') %}
-              {{ default_letter_contact_block | string | nl2br | safe if default_letter_contact_block else 'None'}}
+            {% call field(status='default' if default_letter_contact_block == "Not set" else '') %}
+              {{ default_letter_contact_block | string | nl2br | safe if default_letter_contact_block else 'Not set'}}
               {% if letter_contact_details_count > 1 %}
                 <div class="hint">
                   {{ '…and %d more' | format(letter_contact_details_count - 1) }}
diff --git a/tests/app/main/views/test_service_settings.py b/tests/app/main/views/test_service_settings.py
index 3f5f64feb..1efc246cb 100644
--- a/tests/app/main/views/test_service_settings.py
+++ b/tests/app/main/views/test_service_settings.py
@@ -34,7 +34,7 @@ from tests.conftest import (
 
         'Label Value Action',
         'Send emails On Change',
-        'Email reply to addresses None Change',
+        'Email reply to addresses Not set Change',
 
         'Label Value Action',
         'Send text messages On Change',
@@ -53,7 +53,7 @@ from tests.conftest import (
 
         'Label Value Action',
         'Send emails On Change',
-        'Email reply to addresses None Change',
+        'Email reply to addresses Not set Change',
 
         'Label Value Action',
         'Send text messages On Change',
@@ -115,7 +115,7 @@ def test_should_show_overview(
         'Text message sender 0781239871',
         'International text messages On Change',
         'Receive text messages On Change',
-        'API endpoint for received text messages None Change',
+        'API endpoint for received text messages Not set Change',
 
         'Label Value Action',
         'Send letters Off Change',
@@ -252,7 +252,7 @@ def test_letter_contact_block_shows_none_if_not_set(
 
     page = BeautifulSoup(response.data.decode('utf-8'), 'html.parser')
     div = page.find_all('tr')[8].find_all('td')[1].div
-    assert div.text.strip() == 'None'
+    assert div.text.strip() == 'Not set'
     assert 'default' in div.attrs['class'][0]