Hey Michael,
You may have tried this but it's a common problem. The key hole for the boot is kinda hard to see and you may have overlooked it. It is located right in the middle of the XK-8 badge on the back of the car. The Valet parking release is in the very back of the center console.
Good luck. If you already knew this, good for you, if not, I hope it helps.
Don
