If anyone is interested I have a friend (not internet connected) who owns a '42 G3L which is for sale.
The bike attended the "65 for 65" event, and the 70th, taking part in both the record attempt at Etreham and the Bayeux liberation parade. Currently it is located in Taunton, comes complete and roadworthy, including a spare engine.
Contact me by email and I'll pass on contact details, price, accessibility etc