Have noticed on a few deal sites that people are getting messages from Asda cancelling the item. Also be careful as there is a disclaimer on the site "Please note that these prices are for guidance only. You will be charged the in-store price of all available items on the day they are delivered."

So if they do deliver check the receipt before you accept the goods. I would be looking at an £800 bill if i were to pay full price. They only take payment once you take delivery.