its always like that for uk prices, take the us price and put pound on the end or vice versa sucks but true.
It's like that everywhere in Europe with the pound and euro. It sucks for us American's to vacation there because a beer is going to cost the same except with either a pound or euro on the end. It's the same with cars in the U.S. Foreign manufacturers rely on volume from the U.S. market and that is why they can sell it cheaper.
I would just go on vacation to the US and purchase a ton of lenses from BHPhoto with the exchange rate's buying power.