GQ2 that could well be the case, given that Mosquito Squadron was filmed at Bovingdon.
My late Father was the Adj of 617 GS at Bovingdon in 69 and 70 and took me there as a youngster on many occasions. I well remember the 3 Proctors mocked up as Stukas being stored in one of the hangars, along with the large painting of Buckingham Palace (done for the shot where the 'Heinkel' flies low over the Palace before crashing into Victoria Station) and some of the Buchons which had been made to look like P51s.