Buying a 2008 e60 520d...

I'm contemplating buying a 2008 e60 520d, it's a low mileage example in very good condition, along with a full BMW service history.

The car in question ticks most of the boxes but I'm looking for more concrete information regarding the Timing Chain problems.

I have previously owned a 06 e60 520d which never have me a days bother, and before anyone states, I know they are a better, more reliable engine!

Am I right in being apprehensive regarding the same? What preventative measures can be undertaken to counteract the problem?

All information will be greatly appreciated.

Sean