I only have a few copies from ledgers prior to 1936 (the main WD production had not yet started) but in my opinion, the number combination is possible (Engines and frames at Norton were pre-numbered and used as required, sometimes thousands out of sequence !)
I've found numbers fairly close and they all date from March - June 1934.
The same frame was used at this time for Models 1 (Big 4), 16H, 18, 19 and 20 and only the factory records could confirm what was originally fitted. The frame would be the correct type for either SV or OHV engines and 500 or 600cc
Why do you think that it's a 'bitsa' ?
One thing to watch out for is that WD16H replacement frames were often taken into service use without a stamped 'W' prefix....
Hi Rik the reason I think its a bitsa is there was a 16H engine which the seller has now sold this was I think the original engine for bike.The engine now fitted is either a model 18 or 19 ohv,I shall have to get bike outside to get a better look as its rather dark in this barn.I dont really care if bike is original or not as its a nice bike but obviously orginality affects the price so would be handy to know....Dave
email (option): alliedglass123atgmail.com replace the at with @
It all looks correct for 1934/35 to me. Very nice. With no pre-war matching numbers, I'm not sure that a replacement engine from the correct year would make a great deal of difference except at the very top end of the market (OHC etc.
The only way to tell for sure would be an enquiry to the NOC or the VMCC.