Anecdotal input for you -- I've had a preliminary interview with a group in London which might end up hiring me (from the US no less) and which is more likely to be paying around £70k/yr -- the highest I've seen. Stuff on the order of £50k seems to be more common. Overall it seems like a step down from New York, given that it's also just as expensive, but it's hardly as bad as what you've seen...