Next pillowtop mattress bargain, is it worth it?

Hi, we have just purchased a 'pillow top' mattress....and having read read all the above I am thinking it was a duff buy...however it was reduced at our Next clearance from £1100 to £450, it has 2000 pocked springs and I believe is the same as the link here:
I am hoping it will be OK durability wise, if not my thoughts are well for £450 we could use the bottom reverse side if need be and place a topper on if need be later?
I value your opinion!