I had the exact same problem on my last golf and now on my new one, all i did was use clear silicone around the passenger side of the windcreen seal , wiped it in with my finger, then wiped all the excess away with a solvent wipe untill there was no excess sealant and it worked a treat. haven't got around to doing it to my new mk 2 though as it always seems to be wet and i dont have a garage to do it in.