Yes, like English Rose said, the Tax rate depends on your income. If for example your income is £100,000, expect to lose £40-50000 in tax, but if your income is lower, the tax percentage decreases accordingly.
So there are tax brackets, they change regularly, so go to the "HM Revenue and Customs" website and check there.
Regarding "Cost of Living", it rather depends what standard of life you wish to have. Should you wish to have a lavish life, it will be suitably expensive. If you live frugally, it will be less expensive . . .
but ...
I must echo what someone else said ... London is an EXPENSIVE city.
I have very well paid friends who work in London making LOTS of money, who are still forced to share a house with people, because he can't afford to rent his own flat.
It's all about priorities . . .
I hope i helped in some small way
