I've seen that picture before Ron! Wonder when it was published... Does anybody know?
Anyway, I've dug a bit deeper in my archives. Found this RAOC Receipt Card for contract C/8331:
It looks as if census numbers C4461718 - C4461741 had been allotted. But these numbers have been crossed out... because the Triumph factory was destroyed during the Coventry Blitz before anything had been delivered...?
It must have taken some time to set up a new factory in Meriden. And there must have been a plan to build these bikes from the remaining parts. A new batch of 50 census numbers was created: C4854130 - C4854179. According to the front of this card, Chilwell received 12 bikes, at the back they mention 10 deliveries, on 1/12/42 (on "day 322", which was a weird day counting system that Chilwell was using). Ten or twelve bikes instead of fifty... Maybe that's all they could rescue from the bombed factory? And by late 1942 all WD motorcycles had "universal" pannier frames, metal frame pillion seats, 6" headlight with blackout mask, convoy tail lamp... This would explain the setup of the bike in the first picture of this thread, and also the picture from Ron's previous post... but that bike seems to have a pair of modified pannier frames and no pillion seat. I bet the bike in the first picture has also got these modified pannier frames, but we can't see them through the pannier bags... More research is needed here... Also about the fact that this engine was discovered in France. It definitely can't have been one of the two test bikes that had been sent to the BEF, that's for sure. But it's a fascinating project nevertheless!