An observation I have made on this thread is that Paul RS has obtained a Finis No without a reg no by simply selecting the relevant items in the drop down menu for either Sierra or Escos on microcat Alhough he has stated that it may not be the correct part. but it was certainly more helpful than the guy in Ford.
When I had a copy of microcat, I would look up the part no's before going to Ford to order anything up.