As a comparative youngster I was converting onto the Canberra at Cottesmore in 1972. One of the nav instructors told me he was one of the navs used flying the Lancs in the film, and, though he enjoyed the flying, said what a tight fisted outfit the producers were. As a thanks to the real aircrew involved they put on a barrel of beer in the Officer’s mess at Hemeswell. This was because the Mess at Scampton had changed, and they used clips from this party in the film itself.