Hi I just wanted to add to this thread and say and MASSIVE THANK YOU to you guys for highlighting this issue and the fix. My 2013 XF Sportbrake had a failed alternator. When swopped I got the double beep mislock. Long story short been hunting for the solution for ages getting the SDD software, blah, blah. Eventually found this thread and phoned local garage with Autologic software. Took the printout of this thread and 15 mins and £54 later problem fixed !
The garage for reference was All Trans Autos in Stanway, Colchester. They managed to fit me in within a week. The local Jag dealer couldn't see me for a month, wanted £168 to hook up their machine and seemingly from this thread wouldn't have known how to fix it. They started saying it was probably a door lock..... All power to the internet and the posters on here.
Cheers Mike