A question for the Techies out there. Have recently acquired a 54 reg motor with the above engine ( albeit with very low mileage ). Having read the various related forums its become apparent that this unit has issues with Cam Timing slipping despite being chain drive ! I understand that during its life at some point a modified Tensioner was brought out and wondered a) if this cam problem is just an isolated fault and nothing much to worry about if indeed VAG created modified parts and of course c) from which engine number was this incorporated as standard?

Any help greatfully received from a 54 year old duffer

From what I've read, revised tensioners were fitted starting around 2003.

Your 54 model should be OK.

AFAIK those early tensioners were hydraulically operated.

Most likely cause of failure was lack of oil pressure due to low oil level (i.e. user neglect)

Yeah spot on, they slip when the oil gets low (bottom of the dipstick and turn a corner)