It's worth considering the tailors who work in the Holborn area serving the Inns of Court etc. They tend to be a lot cheaper than the Savile Row tailors, but still of very high quality. Two of the best are Connock and Lockie (about whom I have heard very good things, and I've seen excellent examples of their work), and Sims and Macdonald, both on Lambs Conduit Street. They both do fully bespoke for 1000+ or thereabouts.
Incidentally, if you are really strapped for case, there used to be several small tailor's shops in the same area who do really well-priced OTR/MTM suits in a very limited range of cloths. I suspect their main market is people appearing in court in a rather different capacity those served by the bespoke makers, however I bought two navy and charcoal pinstripe suits from one for when I went off to teach in Japan back in the mid 90s, had them adjusted in store, and they actually fit me me really well. I wish I had kept them now.
