There are loads of decent British made tools, but sadly London is not the place to buy them!
The last 20 to 30 years has seen a huge change in the way tools are sold in the U.K. Back then, every major town had it's own tool shop selling usually decent stuff. Same applied to every London suburb, although Buck and Ryan mentioned above was probably special! Unfortunately, the Rates (local taxes paid by every shop in the U.K.) basically mean that old style tool shops can no longer price stuff at a level they can compete with the Internet, and still make a profit! All but a few are gone!
You will still find hardware shops selling (usually crappy) tools, and many towns have specialists selling tools (as many power tools as hand tools) to the trades, located on industrial estates. None of these really tick the box of an old style tool shop though.
The good news though, is that just about anything is available, either next day, or within a couple of days! Once you know where your partner is staying, just go online and have the stuff sent to that address! The stuff to go for, judging by what my U.S. friends pick up when they are here, are the big European brands such as Stahlwille, Hazet, PB Swiss and so on. Not only are they MUCH cheaper than having stuff shipped to the U.S. there is a greater selection too!
You can either order from British importers (drop me a P.M if you want some names) or direct from Germany (same applies). The Euro is weak at the moment so it's a great time to buy!
Remember also, that you will be paying U.K. tax (VAT) on all this stuff but as a visitor you can claim that back as you leave! This takes another 20% off the price!
P.s. I see you are looking for Stahlwille 14a's - Only Quality Tools, a U.K. Firm still has most of these new! Good starting point?
