It seems this is the way for amazon to get around the pre-order price guarantee. Cancel your order, make the item unavailable, readvertise the item as a different listing, and bump up the price by several pounds. :(
Just been clobbered by this one as well. Book pre order cancelled. Email stated they were unable to source the item yet included a link to order EXACTLY the same item. Not even a credible lie! For a company making as much as Amazon is this is just pure avarice. What was the old saying? Pride goeth before the fall!