If its anything like the Mercedes boot lock then it will need an oil spraying into it to free up the barrel. The problem being that no one uses the boot lock as it can be opened through the remote and therefore tends to seize up.
Hi Garrett Here is a link for the XF manual....unlocking the boot/trunk is on page 29 Good luck Trevor http://www.jaguarownersclub.com/forums/uploads/media/XFOwnersHandbook.pdf