I was also thinking it would have been hard to get the gears as soon as it left the ramp if it was down to the self adjusting mechanism. As regards to the "dished" centre plate, I had this several times from a well known re-man supplier that we were a distributor for (crap). You could put it on the pressure plate & see 1-2mm gap on the outer of the lining-again would have been evident from the start.