I wouldn't drill a hole in it or let anyone else do it. The problem is with the seals. You need to keep the moisture out rather than do anything to introduce more moisture.
Michael, what is your dealer saying about this now, I would have thought this issue would have been resolved by now.
Shaf
Nov 2002 TDi Sport, Silver,Black/grey interior,climate. Replaced previous Mar 2001 TDi SE