The 1.8 TC plate is the same as any other 1800 or 1700 clutch plate, there is at least one on EBAY at the moment, and they come up regularly at autojumbles.
I have had a clutch plate from ebay, that said it was for a 1.8ltr. However it is still not the correct one. Does any one know what the correct one for 1984 1.87 tc ?