London is a rather expensive place to be bootstrapping a startup. What would make it more appealing than Birmingham (nearby, pretty big), Edinburgh (medium-size city, with one of the best UK universities) or any other of the big cities with universities?
If you care for frequent flights to US/Asia, but don't mind the language barrier, Amsterdam or Berlin would be good choices as well. (Living cost in Berlin is relatively cheap yet it's attractive enough to live in for people - Amsterdam is expensive but small enough to commute if you want to live someplace cheaper).
Holland has some very good tax breaks for start-ups. To encourage innovations income from innovations is taxed at 10%. Also if you a foreigner living there, there are some over tax breaks. You can also get tax breaks on employing people.
Berlin is cheap, but hiring people is expensive, but there are loads of start ups there. German Tax laws account for 2/3rd of all tax laws in the world. Somewhere there are tax incentives for R&D investment.
For corporate structure you should look at using a Irish company, as this is far simpler than starting a company in the Netherlands or Germany.
If you care for frequent flights to US/Asia, but don't mind the language barrier, Amsterdam or Berlin would be good choices as well. (Living cost in Berlin is relatively cheap yet it's attractive enough to live in for people - Amsterdam is expensive but small enough to commute if you want to live someplace cheaper).