Sooooo back to the wondscreen. Nobody else seems to have the heated screen?
I have it on my GTD.Since i live in Scotland i use it quite a bit from Nov-Feb.As others have said.It (the diesel) takes an eternity to warm up so i knew i had to have it.Shame about the advanced tele prep crap you have to spec with it-but that's how it is with VW.

Mine is also set to come on automatically when you press the max demist button.I notice it de-ices quicker than it de-mists.I haven't had to switch onto manual heating as yet.Maybe the auto demist function isn't as good as it claims to be?.
I would get VW to check it out.Maybe your heating element is faulty?.