If I may suggest that as a mechanic you surely value the knowledge of a vehicles history, especially the major mechanical (vital) components that have or haven't been replaced. You've owned your L322 since new, you know it inside out, 206xxxKMs isn't huge for a diesel, definitely not a well maintained diesel. Your family might have their own opinion about your lifestyle as you are getting older but do YOU actually have any concerns about your vehicle? Even if something happens that you may not physically be able to repair yourself, do you not have someone to help you with that if need be?
You could follow advice given by others (especially family) through concern and be just another elderly man given up in a Camry or Accord, or make your own choice, if you don't feel any attachment or emotion with your Range Rover, sell it and buy something to just get by. If you still enjoy it, keep it until you decide that it is better to not have it. Do you have children or grandchildren who appreciate your vehicle, who you could pass it on to once you are ready?
If your vehicle still gives you joy, keep it until it does not. Because vehicles which make you feel good are more important than vehicles that are just a thing.

