I own a XKR my 2007 and have had my fare share of problems with electrical circuitry in the Jag. After I installed a Battery designed for cars with engine stop and go systems, a AGM Varta battery by the way, my problems became less. They didn't disappear fully though.
10 months ago I tried a trick, I disabled the automatic function of the headlight and windscreen wipers. Since then I haven't encountered any glitches whatsoever. It's worth a try.
Good luck!

 

What problems did you still have, after fitting the AGM battery?

 

The electrical System wouldn't start; The car wouldn't open with the remote; The battery would drain and the headlights and other lamps would light up slightly; the control screen would freeze and airco, stereo, etc wouldn't respond to button touches.

None of that occurred after I disabled the automatic headlight and wiperswitches.
I know it sounds crazy but since then no problems anymore.

 

I would suggest you get that checked out. Whether it be the headlights or the stalk itself but something on that circuit is putting a parasitic drain on your battery.

 

Agreed; that sounds like a fault to me. I leave auto lights and auto wipers on all the time, sometimes my car doesn't move for days. I haven't noticed anything as serious as that.

Twice recently I have started the car and the touch screen gets stuck at the Jaguar leaper logo but it's fine after I switch the car off and back on again. I have been doing a lot of fairly short trips recently so I put it down to that. I do have an AGM battery fitted but short trips will still drain the battery more than they'll charge it.