The film in question of the Lancaster going down is to the best of my knowledge ; 617 Sqn BI (Special) PD117 (YZ-L) on 21 March 1945 during the Arbergan rail bridge, Bremen. attack.
The Lancaster has been hit by flak in the target area. F/Lt BA Gumbley DFM Pilot, F/O EA Barnett F/E, F/O K Gill DFC CdG Nav, F/L JC Randon B/A and F/O G Bell A/g were tragically all killed. The aircraft went down with it's Tallboy still onboard. The attack was carried out by 20 aircraft with 18 carrying Tallboys, and 2 armed with Grand Slams.The raid was filmed by the BC Film Unit (463 RAAF Sqn)
F/Lt .Bert Gumbley RNZAF had completed his first tour with 49 Sqn Scampton /Fiskerton in 1942/43.