Prob a bit late but read it and had an idea, battery in boot, alternator in front. lead going from alternator to battery. should be able to get another battery/power source connect negative to engine somewhere [earth] and clip positive to terminal on back of alternator [prob biggest wire there] and try to open boot. should be enough power there to work some electronics - just dont try to start engine or any other heavy loads with it connected like this. i couldnt see that it would do any harm. [although i take no responsibilty, i would try this myself]. OR bump start the car, the alternator should give enough juice to keep it all alive till you switch it off. i would try the first one first.