My rear offside parking brake siezed too, but it seized in a partially on / partially off position. My mechanic pointed out a crack in the plastic motor housing on the caliper which he said had prolly caused water ingress which over time siezed the caliper. Bit strange having such an important part of the safety equipment of the car made out of such a volatile material i thought. Anyway, he replaced the caliper with a recon and charged £220, so unless you have to use VW dealer for some reason i'd shop around for a cheaper alternative.

Good luck mate.