Hi oblivion441,
While I'm sure that you could find a GMAT tutor in London, it's not clear whether you actually need that type of study resource at that point. Before you spend a lot of money on that type of service, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied?
2) What study materials have you used so far?
3) How have you scored on EACH of your CATs/mocks (including the Quant and Verbal Scaled Scores for EACH)?
4) When did you take the Official GMAT and what were the Quant and Verbal Scaled Scores for that Exam?
Goals:
5) When are you planning to retake the GMAT?
6) When are you planning to apply to Business School?
7) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich