Well I have had the exact same problems with my ZT-T (the sporting 75) clutch. OEM parts from LUK failed after 3000miles. Anyone who owns one of these will know that this is a big problem and is the same from all of the suppliers with all showing similar failures. Same issue with these cars with drop links, ball joints, etc. all OEM from reputable suppliers (or supposedly).
My Dolomite I've had rad hoses that do not fit, NOS clutch master rusted in bore, clutch pivot pin, nothing like the one in pictures of supplier, brake hoses failing in no time OEM branded, ball joint covers disintegrating within two years (from the club), Distributor caps out of centre, condensers, utter crap, all from reputable suppliers and in most cases all that's available. We have to rely on these suppliers, who advertise in our club mag, that what they sell us is of good quality, but in general a lot of it isn't. I know that the market does not warrant the investment in tooling for the numbers produced as we will not pay the resultant price. This is direct from the suppliers customer feed back. We will happily pay £4.95 for a distributer cap that is garbage with the posts out of centre and not £30.00 or thereabouts for one that will last a lifetime. Its not worth tooling up to make hoses that fit for the numbers that will be sold so we have to take what we get.
It is an example of market failure, it why you need regulations. If parts had to meet a minimum standard and there was proper enforcement of the rules. It would be impossible for bad companies to undercut the good ones.