The Army used about 900 buses in France during the early part of the war, as troop carriers, mobile pigeon lofts, gun platforms, etc. There were 34 of them at Arras alone so I don't see why folks can't see a use for them. They're no different than GS trucks or wagons, other than possibly being a lot more colourful. They're simply big taxis. They were originally left in their working liveries but later received some 'armour' as shown and a coat of khaki. The survivors were sent back to England and returned to work on their routes.
Old Bill was one of the original war buses and is still preserved at the IWM. It was even used as a hearse for old soldiers after the war.
