Jim, I can't provide much info about these wrenches. My list of T Williams Superslims only comes from searching eBay and waiting for the missing wrenches to show up at an affordable price. I can only guess that these were sometimes supplied with auto kits and that they date from the 50's-60's.
From Grace's Guide - Williams, T. (Drop Forgings & Tools), Ltd. Stand A,618 Tilton Road Works, Tilton Road, Birmingham, 9. Teleph.: Victoria 3451/2/3. Tel. Add.: Victoria 3451/2/3.-Engineers' and Motorists' Tools. Superslim Ring, Open Jaw, Adjustable Wrenches, Pliers, Pincers, Screwdrivers, Tool Kits. Precision Ferrous Drop Forgings either Rough or Finished, Machined for the Motor and Engineering Industries.
I'll try asking on Britbike.com forum and see if any of the guys can tell me more.