Hi
connect it directly to the battery, make sure it has a inline fuse on the positive as close to the battery as possible
then just have the plug in the boot where its easy to access
I have the genuine jaguar ctek in mine, that cam with a proper socket thats mounted in the boot side carpet, so you just open the boot and plug the charger in, the boot can be closed while its on charge, the boot seal wont damage the cable, but make sure the battery vent pipe is still fitted, some people dont bother with the vent pipe on the battery, but it vent dangerous explosive gases out of the car, not trapped in the boot
cheers
Joe