I had a coolant issue, whereby it would always leak on the near side, just under the front corner, of the front valance. It was simply a jubilee clip, done up too tight, that in time made the bacolite piping perish.
But having looked back through the history of my car, I can see that the only, previous, poor woman owner, had spent nearly £300 over the course of a two year period, trying to diagnose the problem with her local VW dealer and probably whole a lot more on coolant and all to no avail......what bastards some of these main dealers are!