Welcome. We have quite a few other members from the UK here, including a couple active on this vintage discussion board.Hi I’ve just signed up in the UK
We have a thread dedicated to JH Williams tools. If you're interested in drawing more attention to JH Williams collectors and for having your "spanner" (engineers' wrench) be a part of the knowledge and discussion base on JH Williams tools, you could re-post these photos there. You can find it in the A-Z Index of threads in the sticky at the top of the forum that reads READ B4 POSTING! I plan to x-link your post to the end of that thread, bump the thread, and tag you there to reply, so that your wrench and my reply and any ensuing discussions will have a more lasting purpose and consolidate JH Williams tools and discussion for future searches etc.Having a clear out of the old spanners and came across a “J H Williams spanner
It has the diamond W inside the Williams oval and raised W on one side with the number 33 and the letter C on the other.
No size markings that I can see.
No. Those would be the USS nut and bolt sizes a "33" (milled openings 7/8" x 31/32") would fit. If that "C" stamp is factory, it's likely a 33-C though.1/2 x 9/16 it appears