Whereabouts was that from? I bought some advertised at about that price which were listed for the 180, turned out to be for the 4 pots!!
Double check the disc size it should be 282mm on the fronts, I would bet my left nut they have listed it wrong, it's unfortunately quite common for companies (especially on ebay) to list them wrong.
If they are the right size then that's a good deal as the cheapest I could find the correct size mintex for was £139
Check these out mate, there are others but these are the correct sizes etc:
http://www.ebay.co.uk/itm/ROVER-MG-Z...8#ht_907wt_952