I managed to get this as a pricematch deal - it works out as the cheapest in the UK by a decent margin.
PC World have it in stock for a ludicrous £319.97.
Play.com have it in stock for £139.99 delivered, but using the 5% off promotion, it comes to £132.99 delivered (PC World seemed to be fine with the discount applied)http://www.play.com/PC/PCs/4-/3479040/-/Product.html
This makes the difference between the two £186.98. PC World currently have a pricematch promotion of 110% of the difference.http://www.pcworld.co.uk/martprd/editorial/price-match-promise
This means that the pricematch discount is £205.68, taking the total price to £114.29. It took a lot of patience and debate with the manager, but I did manage to get this price. He did have to call head office though, so I'm not sure how long they will be selling it for £319.97 though. You'll need a printout from play.com.