Without wishing to duplicate a post, could I just add a few “update” comments, having the same problem and looking at every forum I can think of! Firstly, this is a common Jag problem and not restricted to XKs; indeed, I understand Jaguar issued a modified fuel filler neck for the XF. It may be related to oversensitive pump sensors, of course, but actually in some cases, its the car not the pump! Also, note, the filler system is different (on XKs,) between EU and NA models, so likely that the EVAP canister problem suggested on many forums does not cause the issue on UK cars. The other point to be aware of is that most JLR dealerships will “claim” ignorance of it being a car problem, (mine certainly did!)
if you are unlucky to have a vehicle that suffers, then please try all the self help suggestions ie angling the nozzle, turning it to 90 degrees etc. It may work! However, there are clearly some problem cars which no matter what you try, the slow fill problem may persist. Very sadly, I have not yet stumbled upon the solution, and as mentioned, not getting any help or advice from JLR either. The problem certainly seems more prevalent as the tank fills to ward’s capacity, and to make matters even more frustrating, sometimes filling up works okay. It is not related to different pumps either, because I can only access one pump locally with E5, (and before anyone suggests it, happens just as often with E10)
If anyone else has discovered a fix, would be delighted to hear 👂