Popped into Asda today, saw about 5 of these left labelled at £9!! Much cheaper than the cheapest online! currently £10.99 at CDWOW (takes ages to be delivered!! since its from Hong Kong) or £11.68 from Amazon. (1 disc editions)
Not sure how long this is on for this price, it maybe for the first week of release only, which is this week. however £9 for the single disc is a brilliant price since it only came out on monday.