An update on mine, after going back and forth between Dealer and VW customer services they agreed to support the costs. Initially the quote was for £6525 to replace and fit a new engine.
In the end this has cost me £2k fully fitted at main dealer, now have a brand new engine and 2 years warranty
Problem was confirmed as chain tensioner failure, so I have ensured they have also replaced with the latest version.
I picked the car up yesterday and all is good
I must say the dealer has done a very good job, and their service has always been very good since I bought it , they are Ridgeway VW in Reading.