Sorry this is a bit late but many thanks to all of you who replied to my Big 4 post. I haven't done anything with the B4 yet but I now have a new love in the form of a WD 16H, frame number 10087, engine number 10085. This turned up locally, having spent the last 50 years or so in a variety of sheds before ending up in a coal cellar. It's a civilianised bike and still has a Pride and Clark saddle cover. There is a small aluminium plate approximately 3 inches x 1 1/4 inches, riveted to the rear mudguard flap. At first I thought it might be a Pride and Clark dealer plate but after removing thick black paint and grey primer the number 4394898 was revealed and also the date 1.8.50. Could the long number be the contract number and the date the decomissioning date?
There are a few bits missing including the primary outer chain chase, clutch chain wheel and chain, footrests, dynamo, front brake and headlamp rim and reflector but I've got most of these in my Norton stuff that I have hoarded over the years.
Any thoughts or information on the bike would be most welcome.