Decent cells cost alot more than £2
I think it's just an expensive shop, they sell Sanyo Eneloop for about 40% more than they are available elsewhere.
There's a lot of marking-up going on with this sort of stuff, much of it is made in the same factories and re-badged. There may be small variances in quality/capacity, but I think you sometimes pay a significant premium for some brands, beyond any real increase in quality.
I think it's a bit of a minefield these days, many brands charge what they can get away with and it's nothing to do with actual cost of production.
Look at this torch: http://www.flashaholics.co.uk/surefire/surefire-e2l-aa-outdoorsman.html
I'm sure it's very good quality, but £200.00, really?
So, it's more expensive to produce than a television, a washing machine, a bicycle! Is it 15 times better than the similar torch I bought for £15.00, of course not.