diff --git a/app/notify_client/models.py b/app/notify_client/models.py
index 55dbd2f50..3267a0fea 100644
--- a/app/notify_client/models.py
+++ b/app/notify_client/models.py
@@ -183,6 +183,7 @@ class InvitedUser(object):
         self.status = status
         self.created_at = created_at
         self.auth_type = auth_type
+        self.permissions = translate_permissions_from_db_to_admin_roles(self.permissions)
 
     def has_permissions(self, *permissions):
         if self.status == 'cancelled':
@@ -217,7 +218,7 @@ class InvitedUser(object):
         if permissions_as_string:
             data['permissions'] = ','.join(self.permissions)
         else:
-            data['permissions'] = self.permissions
+            data['permissions'] = sorted(self.permissions)
         return data
 
 
diff --git a/app/notify_client/user_api_client.py b/app/notify_client/user_api_client.py
index ac525d695..76968eb9d 100644
--- a/app/notify_client/user_api_client.py
+++ b/app/notify_client/user_api_client.py
@@ -148,8 +148,7 @@ class UserApiClient(NotifyAdminAPIClient):
         # permissions passed in are the combined admin roles, not db permissions
         endpoint = '/service/{}/users/{}'.format(service_id, user_id)
         data = [{'permission': x} for x in translate_permissions_from_admin_roles_to_db(permissions)]
-        resp = self.post(endpoint, data=data)
-        return User(resp['data'], max_failed_login_count=self.max_failed_login_count)
+        self.post(endpoint, data=data)
 
     def add_user_to_organisation(self, org_id, user_id):
         resp = self.post('/organisations/{}/users/{}'.format(org_id, user_id), data={})
diff --git a/tests/app/main/views/test_accept_invite.py b/tests/app/main/views/test_accept_invite.py
index 406a58c47..8f8efaa9d 100644
--- a/tests/app/main/views/test_accept_invite.py
+++ b/tests/app/main/views/test_accept_invite.py
@@ -22,7 +22,7 @@ def test_existing_user_accept_invite_calls_api_and_redirects_to_dashboard(
     mocker,
 ):
     expected_service = service_one['id']
-    expected_permissions = ['send_messages', 'manage_service', 'manage_api_keys']
+    expected_permissions = {'send_messages', 'manage_service', 'manage_api_keys'}
 
     response = client.get(url_for('main.accept_invite', token='thisisnotarealtoken'))
 
@@ -49,7 +49,7 @@ def test_existing_user_with_no_permissions_accept_invite(
 ):
     expected_service = service_one['id']
     sample_invite['permissions'] = ''
-    expected_permissions = []
+    expected_permissions = set()
     mocker.patch('app.invite_api_client.accept_invite', return_value=sample_invite)
 
     response = client.get(url_for('main.accept_invite', token='thisisnotarealtoken'))
@@ -121,7 +121,7 @@ def test_existing_signed_out_user_accept_invite_redirects_to_sign_in(
     mocker,
 ):
     expected_service = service_one['id']
-    expected_permissions = ['send_messages', 'manage_service', 'manage_api_keys']
+    expected_permissions = {'send_messages', 'manage_service', 'manage_api_keys'}
 
     response = client.get(url_for('main.accept_invite', token='thisisnotarealtoken'), follow_redirects=True)
 
@@ -368,7 +368,7 @@ def test_new_invited_user_verifies_and_added_to_service(
 
     # when they post codes back to admin user should be added to
     # service and sent on to dash board
-    expected_permissions = ['send_messages', 'manage_service', 'manage_api_keys']
+    expected_permissions = {'send_messages', 'manage_service', 'manage_api_keys'}
 
     with client.session_transaction() as session:
         new_user_id = session['user_id']
diff --git a/tests/conftest.py b/tests/conftest.py
index 643c30aef..7635a709b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -2052,7 +2052,7 @@ def mock_accept_invite(mocker, sample_invite):
 @pytest.fixture(scope='function')
 def mock_add_user_to_service(mocker, service_one, api_user_active):
     def _add_user(service_id, user_id, permissions):
-        return api_user_active
+        return
 
     return mocker.patch('app.user_api_client.add_user_to_service', side_effect=_add_user)