It is a shame. Its as if they know diesel is the more viable option in the UK so they put a premium on it.
TBH I'm not worried about the DSG gearbox it sounds like a strong piece of kit which has been well developed. There are built in safety functions to stop clutch wear as well as the over cautious ESP torque limiting to keep it safe. They are sealed units where apparently the clutch packs wont need changing for the life of the car. But.. time will tell. I think if there are any problems with engine or box it will be within the first year.
A cupra TDI I would guess would be near 18k. With the new VAT rate a standard Boc is over 17K now!
In the EU is the annual wage higher in comparison to the UK. I just cant fathom how they think charging the equivalent of 21k is OK on the continent!