£250 is more like $375 these days, and yes the cost of living is high here. A cheap room in a flat in London is £500 a month, more importantly a beer is often over £3, I don't know how that compares to the states to be honnest so I won't presume to say its harsher.
And yes, £250 is a bloody good rate for a tour. All power to you if your getting it.
I tend to go in at £200 and I usually get it without argument. There are exceptions and I don't complain about them because if I take a job for less it means I really want to do it, thats the best thing about being freelance!!