I had the same problem with my XKR. It started with a bulb warning light message and developed to the beam dropping out of sight. This happened overnight and was intending to take it to my dealer. I mentioned the problem to a friend, who used to have an XKR. He told me he paid £350 for 'diagnosis' with a dealer, only to find out it was a reduced charge battery problem. I charged my battery up overnight and the problem was gone the next day. If you use heaters for steering wheel, seats, etc in the winter, the battery charge level reduces as the alternator doesn't charge at the rate it uses power, especially on short journeys. My problem was solved easily, I hope this helps you to solve yours.