I had this fault on an '03 Audi A3. The clutch switch was actually burnt! For this car the switch was available seperately, about 30 quid IIRC. Complete pig to change using long nosed pliers and bits of bent wire as I could not bend my forearms in the middle to get my hands in.
I wouldn't be surprised if the master cylinders were the same, it may be that the seperate switch just never got carried over onto the Golf parts list.
Shaun.