Note: This deal is ONLY created for the above store. I can't verify other stores.
I just picked up Guitar Hero World Tour (game only) for the 360 from Woolworths in Kings Heath, Birmingham for £17.99 (originally marked as £35.98). They had about 8 or 9 left.
I appreciate it's not likely to get this deal in all Woolworths (if yours even still exists) but if you're in a Woolies store it's worth checking. Please let others know in the comments if yours has it.