Do you have a power supply to hand and even better a tow bar?
I use a C-Tec conditioner and have made up a link lead using the Neg and permanently live pin in the seven pin plug. The battery is always at peak charge and will not sulfate, the car is locked and the alarm active and when I want to drive away I remove it's case I have attached to the steering wheel as a reminder and unplug at the towing electrics.

The best solution I can think of.