Timing chain/belt on 2006 Jaguar XJ8

I am looking at an used 06 Jaguar XJ8 and have read about potential problem with tensioner,timeing chain etc.
Can anyone enlighten me with what it is?

Asked by for the 2006 Jaguar XJ8
I believe that the issue is limited to the "old" XJ8 from around 1997 -2003 - new models have a different design of tensioner made of metal (not plastic) and so much less likely to fail - my 3.2 V8 is 10 years old and just had tensioners replaced.