Bernard De Smet
If the Hillman was built in 1938 for the RAF, it would certainly have been gloss RAF blue, but then most likely repainted in camouflage colours in Wartime.
BTW - If you ever strip the engine I'd be interested to see photos of the cam driven push rod drive for the fuel pump, as I was working on a Hillman Tilly with a friend who had a problem with the push rod as it seems the end had worn near the cam shaft, so there was no back and forward movement on the rod to work the fuel pump. We had to fit an electric one rather than strip the engine.
If its the cam shaft that's worn a new push rod won't work.