Jack - 2014 L405 Range Rover Luxor Metallic

So, I recently inherited a Range Rover from my grandfather who drove it for 11 years without any issues. Dealer maintained with up to date service history. By the records provided by him and what the dealer who services it says, it's a great car. In their words it is a "unicorn". They have never seen one of that age like mine. Now that it's my car, I have been noticing small things here and there. It makes a ticking/knocking sound when it idles down when it starts after the engine has been warmed up. It also shakes when its turned off. I took it to the dealer and they did a full diagnostic test and drove it and couldn't find anything wrong besides brakes almost need to be replaced. After doing more research, I found some videos of other V6 range rovers with timing chain problems and they sound exactly like mine just much worse. I don't really know what to do because if the dealer can't see the issue it can't be fixed.

Any advice or people who have the same issue? Id like to get it fixed before it gets too bad and or decide if the car is worth keeping. (He upgraded to a new LWB Range Rover)