Just FYI to add to your checklist and sounds to listen for.
I had been hearing some kind of scraping noises from the cam belt area so I took off the cover and found that the cam belt tensioner had failed and was eating in to the cam belt and also the cover plate. You can see in the pics where it has moved forward and now the belt is half way off the tensioner.
Morgan has advised me that this happened because the last place to do maintenance used an improper/outdated tensioner when they replaced it. The up to date tensioners have securing clips so this won't happen.
I have a case similar to 5000 km, since his replacement has traveled 30000 km carefree, the problem must certainly be the machining tolerances not tight enough of the tubular part because the ball bearing remains in perfect working order.