Hi, did you get to the bottom of the boot problem? I had a similar problem on a Jag I worked on, it turned out to be just the earth wire in the harnes between body and boot lid, so in the rubber boot, as the wires will fatigue over their life. The lock would try to move but had a rubbish earth return so wouldn't fully operate. I would slide the boot down and check the integrity of all the wires, if it is the case then simply solder a small piece of wire in to repair it.

Hope this helps.