UK Car Repair: Jaguar XJS 1988, jaguar xjs, fuse box

Question
There is a short that no mechanic in Montreal is able to find with my car, everytime the car is not turned on for 24 hours or more, the battery is dead.  I have bought a few new batteries, but all the mechanics are telling me is that it is a electrical short that they can't find.  Should you be able to help me, I would trully appreciate it.
Thanks in advance.
Lana

Answer
First it is not a short, that would burn out the wiring.  It is a draw, something is using the battery when the ignition is off! Start from basics, buy a simple test light from an auto store. Make sure everything is switched off and the doors are closed. Disconnect the battery negative cable, connect one end of the test light to the open battery terminal and the other end to the loose cable.  The test light should be on as the boot (trunk) is open so the switch has closed.  In the fuse box, under the left knee pad, find and remove the fuse for the boot lights. The test light should now be off. If it is, the draw is in the boot light circuit. if it is still on you have to start removing fuses one at a time until the light goes out, that circuit is where the draw is.  Get back to me when you have done this.