Part of the Gamestation online sale, tucked away on the second page of the PS3 deals (sorry doesn't seem to be available for the 360).
Been looking forward to trying this (it's got 9.0 from IGN and seems more than a shameless tie in) and for a tenner (plus loyalty points or quidco - can't get both I've tried) seems worth a shot, especially with a CEX trade in of £10 or cash for £7.
Amazon £16.50 + 2.03 P&P
Game £18.98 OOS
Gameplay £29.99 OOS
Zavvi £15.85 one month delivery
The Hut 39.85 one month delivery