need trunk access to my 2001 DB7

I have just joined AML and need help big time. I have a 2001 DB7 with a fully dead battery. The key goes into the trunk lock, turns, but the mechanism does not open the lid. The remote trunk light goes on but the trunk does not open as the battery is dead. I have tried to charge the battery through then cigarette lighter with a battery tender trickle charger but it appears that no charging is getting to the battery (charger has been attached for 2 days). I have taken the right rear seat out but can see no access to the trunk space from this area as there is a solid metal wall there. The top is up at the moment. Can anybody come up with some ideas? The car is locked in park. The ignition key turns but obviously, no power when pushing the red start button. I need either trunk access or a way to charge my battery. All suggestions are welcome. Thanks, Larry (ungy)