It could be the mechatronic(Spelling?) module.
Best bet to look on the Vag com owners list and for a few beer tokens I'm sure someone local to you will scan it for you.Any faults should show up and then you have something to wave at the dealers.
If your near Wiltshire I can do it for you.
High Factory Spec Mk4 R32 For Sale (including Sat nav,sunroof,Full leather and cruise)
http://uk-mkivs.net/forums/t/335596.aspx