diff --git a/tests/app/celery/test_tasks.py b/tests/app/celery/test_tasks.py
index 818ad4fc4..4692f8df3 100644
--- a/tests/app/celery/test_tasks.py
+++ b/tests/app/celery/test_tasks.py
@@ -1045,8 +1045,8 @@ def test_dvla_letter_template(sample_letter_notification):
          "subject": sample_letter_notification.template.subject}
     letter = LetterDVLATemplate(t,
                                 sample_letter_notification.personalisation,
-                                12345)
-    assert str(letter) == "140|500|001||201703230012345|||||||||||||A1||A2|A3|A4|A5|A6|A_POST|||||||||23 March 2017<cr><cr><h1>Template subject<normal><cr><cr>Dear Sir/Madam, Hello. Yours Truly, The Government.<cr><cr>"  # noqa
+                                "random-string")
+    assert str(letter) == "140|500|001||random-string|||||||||||||A1||A2|A3|A4|A5|A6|A_POST|||||||||23 March 2017<cr><cr><h1>Template subject<normal><cr><cr>Dear Sir/Madam, Hello. Yours Truly, The Government.<cr><cr>"  # noqa
 
 
 def test_update_job_to_sent_to_dvla(sample_letter_template, sample_letter_job):