diff --git a/app/schema_validation/definitions.py b/app/schema_validation/definitions.py
index e779c5794..0bf163999 100644
--- a/app/schema_validation/definitions.py
+++ b/app/schema_validation/definitions.py
@@ -14,7 +14,6 @@ uuid = {
 
 personalisation = {
     "type": "object",
-    "validationMessage": "should contain key value pairs",
     "code": "1001",  # yet to be implemented
     "link": "link to our error documentation not yet implemented"
 }
diff --git a/tests/app/v2/notifications/test_notification_schemas.py b/tests/app/v2/notifications/test_notification_schemas.py
index 0aafb38cc..83ad8c5f7 100644
--- a/tests/app/v2/notifications/test_notification_schemas.py
+++ b/tests/app/v2/notifications/test_notification_schemas.py
@@ -127,7 +127,7 @@ def test_post_sms_schema_with_personalisation_that_is_not_a_dict():
     error = json.loads(str(e.value))
     assert len(error.get('errors')) == 1
     assert error['errors'] == [{'error': 'ValidationError',
-                                'message': "personalisation should contain key value pairs"}]
+                                'message': "personalisation not_a_dict is not of type object"}]
     assert error.get('status_code') == 400
     assert len(error.keys()) == 2
 
diff --git a/tests/app/v2/notifications/test_post_letter_notifications.py b/tests/app/v2/notifications/test_post_letter_notifications.py
index 66a9004c7..18f36d421 100644
--- a/tests/app/v2/notifications/test_post_letter_notifications.py
+++ b/tests/app/v2/notifications/test_post_letter_notifications.py
@@ -100,6 +100,26 @@ def test_notification_returns_400_for_schema_problems(
     }]
 
 
+def test_notification_returns_400_if_address_doesnt_have_underscores(
+    client,
+    sample_letter_template
+):
+    data = {
+        'template_id': str(sample_letter_template.id),
+        'personalisation': {
+            'address line 1': 'Her Royal Highness Queen Elizabeth II',
+            'postcode': 'SW1 1AA',
+        }
+    }
+
+    error_json = letter_request(client, data, service_id=sample_letter_template.service_id, _expected_status=400)
+
+    assert error_json['status_code'] == 400
+    assert error_json['errors'] == [{
+        'error': 'ValidationError',
+        'message': 'personalisation address_line_1 is a required property'
+    }]
+
 
 def test_returns_a_429_limit_exceeded_if_rate_limit_exceeded(
     client,
diff --git a/tests/app/v2/template/test_template_schemas.py b/tests/app/v2/template/test_template_schemas.py
index 4517ad7e8..1e5a91e11 100644
--- a/tests/app/v2/template/test_template_schemas.py
+++ b/tests/app/v2/template/test_template_schemas.py
@@ -51,11 +51,18 @@ valid_json_post_args = {
 }
 
 invalid_json_post_args = [
-    ({"id": "invalid_uuid", "personalisation": {"key": "value"}}, ["id is not a valid UUID"]),
-    ({"id": str(uuid.uuid4()), "personalisation": "invalid_personalisation"},
-     ["personalisation should contain key value pairs"]),
-    ({"personalisation": "invalid_personalisation"},
-     ["id is a required property", "personalisation should contain key value pairs"])
+    (
+        {"id": "invalid_uuid", "personalisation": {"key": "value"}},
+        ["id is not a valid UUID"]
+    ),
+    (
+        {"id": str(uuid.uuid4()), "personalisation": ['a', 'b']},
+        ["personalisation [a, b] is not of type object"]
+    ),
+    (
+        {"personalisation": "invalid_personalisation"},
+        ["id is a required property", "personalisation invalid_personalisation is not of type object"]
+    )
 ]
 
 valid_json_post_response = {