Yes I know about that film Uncle Jack, and that it was supposed to contain a film of the crash that killed Wally Runciman. I was there as an air cadet selling programmes on the day and we went over to the other side of the airfield (to our HQ) which was beside the Shorts Test Pilot shed. We watched XE 175 being prepared and Wally climbing into the cockpit. He began with two loops, then flew along the flight path with the bomb bay open and then he went into two rolls. In the middle of the second one, while inverted, the plane dropped its nose and flew straight into the ground. It was like an inverted stall. I've tried to get a copy of the AAIB report on the accident but so far with no luck.