Mine had a rattle (particularly when starting, but also generally at tick over) which made the engine sound like a diesel. I complained to to VW garage a couple of times whilst the car was still under warranty. They initially denied there was any problem, then when i pushed them finally replaced the chain, tensioner etc. This was about a week before the end of the warranty, and did fix the problem. Unfortunately the rattle came back about 3 months later and I was told by their service manager that their "responsibility ends once the car is out of warranty" in respect of warranty repairs.
I have been meaning to put my thoughts in writing to them about the above, but haven't got round to it yet...