The engine unit is post WW2, the bike itself was regularly used during WW2. This would probably have been a better idea then the small wheeled Welbike that was the ancestor of the Corgi/Papoose.
I used to go deer hunting with a rifle (M70, M98K, or LE#4Mk1, LE#5Mk1, P14, I have a few) slung over my back. Actually brought a deer home slung on this bike (with the M98K). About 1984.