My Skoda Superb 2003 has clutch judder after half an hour of running only when setting off from a stand still its really quite bad what could it be, surly if it was the clutch going it would happen from the start not after 30 mins.
What mileage has the car done? but on saying that, it depends what the last driver was like! was he / she a clutch rider? your car I would think will be self adjusting, you may need a new clutch Ass, there may be oil on the clutch plate that is another cause.
I think your car has dual mass flywheel which absorbs shocks supposedly. They are known to give trouble. If you look on eBay you will find solid mass flywheel kits from LUK.
Either way it is expensive.