Adrian, wartime WD16H production utilised engine and frame numbers prefixed with 'W'. I can't find 93425 without prefix in the pre-war WD production listings. It would appear to have been a civilian model dispatched mid-1938. By this time, WD machines were being allocated clearly defined batches of numbers.
I'd really need to see some clear pictures of the frame including gearbox, fuel tank and rear chainstay lugs to confirm that it is a WD frame. The most likely explanation is that it has a replacement frame stamped up during a workshop rebuild without a 'W' stamp handy.
The last WD16H made seems to have been an RAF combination numbered W96560.
Engine number W89451 does not appear in any of the currently available contract listings and the factory production records no longer exist. I suspect that it relates to an RAF or RN contract as there were a number around this time but information is incomplete.
Currently, there is an undocumented gap between a known RAF contract ending at W88884 and an army contract commencing W90001
Does your machine have 18" wheels and 7/8" handlebars ?
Many many wartime production WD Norton frames are missing or have a faint W prefix. Absence of the prefix does not mean the frame is pre war only possibly. 93425 is far more likely to be one of the last made late war (ie 1945).
Thank you Rick
Sorry for a late reply , you have helped greatly , I have found a W stamped in the frame under many coats of paint . How can I get my photographs to you . Cheers Adrian
Hello Thank you Keith and sorry for the late reply , I have now found a W stamped in the frame under many coats of paint , Be nice to find out more . Thank you for your help . Cheers Adrian .