While I know something about the various different kitchen and cookware shops in London, I won't pretend by any means that my knowledge is comprehensive, and I would almost be sure something like what I'm looking for must exist.
What I want is a shop that has a truly comprehensive selection of cookware - with an emphasis towards traditional, high-grade, high-performance kitchen basics. I'd like to avoid places whose stock consists mostly of things that are laden with features but sacrifice ultimate performance, places that mostly carry the cheap, low end of the range, and places that take a modern-technology slant on cookware without actually considering whether the technology brings anything in terms of actual performance. Some examples of things I would like to see:
Low-damping, accurate balance scales (at least down to 100 mg accuracy): the real type, where you put weights on one side and what you're measuring on the other.
A broad selection of heavy-gauge, bare-metal (i.e. not non-stick), cake and pie tins.
Forged, high quality hard carbon steel (NOT stainless) knives.
Knife sharpening stones in a comprehensive range of grits. If they have, or can get, genuine natural Japanese waterstones then this is a major plus.
Sandwich-construction pots, without a nonstick interior, with a fully copper core (i.e. no aluminium)
High-sensitivity glass thermometers for a variety of uses.
Portable appliances (beaters, blenders etc.) with high-power commercial-grade motors.
Single-group commercial-grade espresso machines (with a vane pump, temperature gauges, full-size and weight group)
A real pudding cloth made of fine, tightly woven fabric.
(OK, a real dream here, probably impossible) A small grinding mill capable of milling both dry grains and oily nuts to 10 micron particle size or thereabouts - generally something that can produce the very finest flours and nut pastes.
Maybe not all of these are to be found at one location (or even, in some cases, possibly at all any more) but I'd love to know some sources if you have any to suggest.