According to the book "Spitfire Dive-Bombers versus the V2", the Spitfire MH693 was used by 303 (Polish) Sqn in UK on 31 March 1945. I guess it is a typo (the books also list MA683 in the list of aircraft for the squadron, so possibly is it a typo/bad decoding for this).
Check the Google preview here:
https://books.google.fr/books?id=s9a...Spitfire+MH693