If they are commonly fitted to other mk1's,perhaps a higher trim level , you may find a good used one. .
There are specialist part finder websites. You enter the part you need free of charge, and various car breakers send you their price. You can pay using the sites own secure payment system. Some cars that are being broken are listed on Ebay, maybe for 99p . For this you would only get a wheel nut . But you contact the seller about the part you really want.