diff --git a/app/celery/letters_pdf_tasks.py b/app/celery/letters_pdf_tasks.py
index a40f2bd91..485f258bf 100644
--- a/app/celery/letters_pdf_tasks.py
+++ b/app/celery/letters_pdf_tasks.py
@@ -261,7 +261,9 @@ def _sanitise_precompiled_pdf(self, notification, precompiled_pdf):
                 current_app.config['TEMPLATE_PREVIEW_API_HOST']
             ),
             data=precompiled_pdf,
-            headers={'Authorization': 'Token {}'.format(current_app.config['TEMPLATE_PREVIEW_API_KEY'])}
+            headers={'Authorization': 'Token {}'.format(current_app.config['TEMPLATE_PREVIEW_API_KEY']),
+                     'Service-ID': str(notification.service_id),
+                     'Notification-ID': str(notification.id)}
         )
         resp.raise_for_status()
         return resp.content
diff --git a/tests/app/celery/test_letters_pdf_tasks.py b/tests/app/celery/test_letters_pdf_tasks.py
index 4af7edca2..13815ce05 100644
--- a/tests/app/celery/test_letters_pdf_tasks.py
+++ b/tests/app/celery/test_letters_pdf_tasks.py
@@ -508,6 +508,27 @@ def test_sanitise_precompiled_pdf_returns_none_on_validation_error(rmock, sample
     assert res is None
 
 
+def test_sanitise_precompiled_pdf_passes_the_service_id_and_notification_id_to_template_preview(
+    mocker,
+    sample_letter_notification,
+):
+    tp_mock = mocker.patch('app.celery.letters_pdf_tasks.requests_post')
+    sample_letter_notification.status = NOTIFICATION_PENDING_VIRUS_CHECK
+    mock_celery = Mock(**{'retry.side_effect': Retry})
+    _sanitise_precompiled_pdf(mock_celery, sample_letter_notification, b'old_pdf')
+
+    service_id = str(sample_letter_notification.service_id)
+    notification_id = str(sample_letter_notification.id)
+
+    tp_mock.assert_called_once_with(
+        'http://localhost:9999/precompiled/sanitise',
+        data=b'old_pdf',
+        headers={'Authorization': 'Token my-secret-key',
+                 'Service-ID': service_id,
+                 'Notification-ID': notification_id}
+    )
+
+
 def test_sanitise_precompiled_pdf_retries_on_http_error(rmock, sample_letter_notification):
     sample_letter_notification.status = NOTIFICATION_PENDING_VIRUS_CHECK
     rmock.post('http://localhost:9999/precompiled/sanitise', content=b'new_pdf', status_code=500)