Just been to my local HMV where they are selling the RockBand Drumkit for £19.99. The price is currently £17.99 on the website however you can't order. http://hmv.com/hmvweb/displayProductDetails.do?ctx=280;-1;-1;-1;-1&sku=799467
My local one had 4/5 for PS3/360.
They also had reasonible pricing on the games too
Rockband 2 - £29.99
Rockband - £19.99
Not the best prices ever but not bad.