I still don't understand who is buying cards at these prices. A 1070 for £650 is bonkers. If used for mining the payback will be over a year and that is assuming difficulty rises make payback even possible.
I've been looking at used, lower end cards on eBay, 1050 and 1050Ti, I gather these aren't much cop for mining but the prices are silly. More often than not a used card on eBay is going for more than (or within a tenner) a brand new card from the cheapest retailer of the day. Why is anyone mad enough to buy a second hand card, with the potential issues that come with it, over a brand new one from a decent retailer?