Couldn't find the thread discussing this but I had a water buildup issue with the Mark 6 camera I fitted to my Mark 5 and I've come up with a solution ala the Mark 6.
Installing a Golf Mark VI Rear View Camera (RVC) into a Golf Mark V
Volkswagen Golf Mark VI Rear View Camera (RVC) In Operation
Install drainage for the Golf Mark VI Rear View Camera (RVC) installed in a Golf Mark V
edit: google found the thread, watercooled search seems to be screwed ATM.
Installing a Golf Mark VI Rear View Camera (RVC) into a Golf Mark V
Volkswagen Golf Mark VI Rear View Camera (RVC) In Operation
Install drainage for the Golf Mark VI Rear View Camera (RVC) installed in a Golf Mark V
edit: google found the thread, watercooled search seems to be screwed ATM.