Worth being careful on ebay, I hear the "mintex" ones are fakes, although it shows you mintex branded packaging in the photo, you actually get unbranded ones. Wouldn't risk it. Sounds almost certainly like your bearings are fooked. You may not feel a wobble when you jack the car as the caliper and pads are holding the disc in place, so prevent any wobble. To be sure, whip the caliper off and then wobble if you feel nothing just wobbling. Rear bearings don't last long on these, especially if you give the car a punishing. It may be worth giving the outer edge and inner portions of the disc a coating in your preferred high temp paint, as the discs can last ages, as long as they don't succumb to rust, and you are prepared to replace the bearing from within the disc. Banter in the earlier part of this thread was incredible, I hope it was light hearted... enough...