Steven, I'm not a traveller. I've lived in the UK for almost 20
years, and I shop in London once a fortnight.
People (in London) are always saying how marvellous London food is
nowadays, which generally results in a kind of boosterism rather than
a thorough assessment. Actually bread in even top restaurants is
often seriously substandard: Gordon Ramsay, for example, buys it in
from bakeoff land. And it shows. Of the top joints, only the Fat
Duck had acceptable bread. Note that I said acceptable. Raymond
Blanc's at the manoir was stale, last time I ate there. I love Le
Champignon Sauvage, but the bread was the weak point of the whole
enterprise. Compare and contrast with Veyrat, Bras, Savoy, Le Grand
Vefour - hell, even Flora or Hélène Darroze.
Opinions differ healthily. From your list, I think no baker would
rival the best of Paris, Venice, SanFran or NYC. Maybe the London
Poilane, but that IS the best of Paris and not indigenous. I thought
De Gustibus's much touted bread dreadful (really dreadful), and Baker
and Spice not much better. I'm also not fond of Euphorium or Flour
Power City (industries). Clarke's is too concerned with flavoured
bread (rather like Poujauran). For me, none of the bakeries you cite
is a patch on St John, but Lighthouse is about the pick of them. Oh,
and Hobbs House in Tetbury (Gloucestershire) is perfectly ok but not
in any way great.
Sorry, folks. Still some distance to travel for a good loaf.