For those struggling to find stock on the Gamestation deal at £14.99 (I tried about 4 different stores in the North West), I was in Game Warrington this morning and they had at least 3 copies of GH Aerosmith on Xbox360 for £19.99 with the free wired guitar same as Gamestation (from Guitar Hero 2/Argos deal), so bagged myself one. Limited stock on the guitars so probably worth a ring to your local store before making the journey.
Store finder, http://www.game.co.uk/Help/StoreFinder.aspx
Hope it helps someone. :)