Nice to see this thread again, little update, there is a guy in Tilburg, who owns an M20, and has painted these markings and C number on his bike, I told him the real bike already existed in the UK, but he didn't care.
In the meantime I also have a bike, a 1940 numbers matching Royal Enfield WD-C, that has been identified from a wartime picture, and think there are more bikes now?
I also own a Welbike, that came from Italy, and was one of 2, that the 6th Airborne para's rode around on delivering messages in Taranto Italy, here the picture, where the veteran Ted Poulton is sitting on it, with uncle Ron! Ted was an avid motorcyclist, and rode a Matchless G3L, well into his 80's, I have his wartime history, should write an article about him one day, he passed away about 4? years ago, RIP Ted.
Cheers,
Lex
email (option): welbike@welb***.net