Hi Ally,
Thanks for your reply, I live on the Costa Brava, in Roses, near the French border.
I have a cousin who has a house in Javea, about six hours drive south.
Do you leave the trickle charger on all the time? I have one for my motor bike which should do the job.
The boot lights are not the problem on my car and I never leave the stereo on, so this would seem to be a solution.
Thanks to everyone who replied to my post