Noel B over on the WW2 Forum told me he had been reading a history of the Automobile Association (AA) which said AA patrols had been praised for their part in the British Army exercises of 1935 or 1936 as military police.
(It also turns out that there was a traffic control unit with the BEF drawn almost entirely from AA staff which suffered very heavy casualties in the retreat to Dunkirk).
Of course I had to field them (the 1930s unit). Oxford Diecast came to the party with BSA m/cs and then also in the last couple of weeks issued an Austin 7 RN van in AA colours. Dart Miniatures provided the AA Patrolman. I think I might keep looking for a suitable standing figure to go with the Austin (preferably standing and saluting) - I may have one in the spares box somewhere.
The only thing I did to any of the vehicles was paint the fire extinguishers on the sidecars silver. I didn't want to mess with the livery.
Here they are in all their glory: