My LHBS is expensive for that sort of stuff too.
In general they are around a pound or 2 more expensive on kits and on the smaller consumables, considerably more expensive.
I think it's due to suply and demand, the owner of ours told me that he got a load of different yeasts in on request from a few guys and most of it ended up going out of date as the guys never bought it regularly enough for him to make it a viable stock item.
Alot of the LHBS don't sell the quantities that the bigger organisations do and if like my LHBS they don't do internet sales (the guy running it is about 70) then they have to hike their prices up just to keep ticking over.
I buy my kits and other odd bits from him, he is a pound or 2 more expensive than on the net, but i don't have to pay for delivery so it ends up being £3 to £4 cheaper in the long run, and there's plenty of banter and advice too.
Andy