Hi Plunk47
I've just stumbled across your post re the Rover car.
I am doing similar research for a friend who has a 1925 Rover 14/45 which was owned by the HB family. He thinks it may have RAF connections, and the original paintwork was badly over-sprayed in RAF blue.
It had modifications to the carburettor and a tow-bar fitted.
I have found a reference to Sir Thomas-Houston RAFVR which seems to confirm the RAF connection, presumably with RAF Chartehall?
Kind regards,
Roger