This is a curious piece of propaganda, “Train Busting Mustangs” – a Pathe newsreel. Whilst not identified this film is dated 1943 and noting the names and aircraft serials it appears to feature Mustang I’s of 400 Squadron. 400 Sqdn. had their Tomahawks replaced with Mustangs in July 1942. Whilst the gun-camera footage looks to be from a variety of different sources, some of the ground scenes look to be Dunsfold.
Two notable names are Flight Officers “Bitsy” Grant and J Morton:
MORTON, F/L John Alexander (J7451) – Distinguished Flying Cross – No.400 Squadron
GRANT, F/O Duncan Marshall (J5982) – Distinguished Flying Cross – No.400 Squadron