The FB Mark VI Mosquito had a shorter bomb bay capable of carrying two bombs. The aircraft used in the film were mainly TT35s with a full length bomb bay capable of carrying four bombs. In Frederick E Smith’s 1956 novel of ‘633 Squadron’ and subsequent sequels it was explained that the Mosquitos were a hybrid type with a full-length bomb bay,two short barrelled 20mm cannon and two 0.303 Brownings.