there are 3 seals, a felt like seal between the plastic button and the tailgate, which for some reason isnt listed as a replacement part for mk3, need to buy the entire lock?
and 2 round thin washer type seals between the lock and the plastic button, and between the rear clip and the lock cylinder:
111 837 227 B - seal between lock and button - 1.55+VAT
N 900 989 01 - seal between circlip and lock - 0.71+VAT