Its 1950 or later based on Heron G-ALZL registered 3/1950 (G-INFO)…. but the Brab was at the 1950 and 1951 show….googling Farnborough 1950, 1951, 1952 brings up youtubes and Pathe/Shell newsreels to help the detectives 🙂
I would think the camera was a bit better than a Box Brownie perhaps with a better lens and adjustable faster shutter