Massive big up for Will, good 15min chat while outside Halfrauds.
His recommendation was 5/40 and they all leak a little and have a little drinking habit.
If they don't leave any little deposits when parked, then the leaks are not an issue.
So, I'll give her a good top up and test drive tomorrow and see if the rattling stops.
He also said that on the R53 engine, the timing chain tensioner change is not as simple as the R56 is. The head needs to come off to be able set the adjuster correctly. So when the head is off the seal/gaskets can get done as well as the seals on the intercooler.
Thanks Will, if only I was close enough to use you - hummm, maybe worth it.