XM flat battery

[beemernut]

I've been offered an XM f.o.c., the problem is that the doors only open on the remote (the key has the end broken off it) and the battery has gone flat as the car has been standing for a couple of months. Any suggestions as to how to get either into the car to open the bonnet then charge the battery etc or open the bonnet to try jumping the battery with a fully charged one to get the remote to activate?