No error lights on when engine running.
Management system was checked by my local service garage (not VW dealer) and they didn't specify the actual error code but said that there was an error with system " finding camshaft timing" which indicated timing chain wear. The timing chain hadn't jumped any cogs but the guides and tensioner were badly worn and therefore replaced.
Check engine light OFF when engine running before and after timing chain replacement.
I initially thought that poor starting might be linked to timing chain wear, but now wonder whether the poor starting is a separate problem.
No error lights on dash before taking car to service garage nor after having chain, guides and tensioner replaced. The plug in diagnostics test they performed indicated a problem that pointed to chain tension problem - the chain, chain guides and tensioner were all found to be badly worn and were replaced, but I don't know the actual error code.
Unfortunately the car is now with my daughter, 200 miles away, so if problem gets any worse she'll have to take it to another garage.