I have a 2010 D4 and agonized at the 3 year mark whether to buy the extended warranty. As the vehicle had been perfect I decided to give it a miss.
At 4.5 years and 66,000km the high pressure fuel pump failed on a caravan trip and was towed back to the closest dealer. As I had serviced the D4 at a dealer up to that point, Land Rover replaced the HPFP & Low pressure pump under a Good Will warranty without any problems. I did cover some of the initial diagnostic costs plus testing of the injectors and cleaning of the fuel system. All up it cost me approx $1000, which I thought was quite reasonable in the end.

