They're in the WS19 archive - Instruction book & repair parts list, First Echelon Work, etc. I'll have a look...
Doc 1803 is the user handbook and contains the circuit diagram, but is a Truly Appalling scan.
Doc 1598 for the post-WW2 BSA equivalent is a much better bet and a lot easier to read. They're the same basic machine.
Chris.
