Hi, have used a slightly different approach. I mounted a small permanent tricke charger on an alumium bracket, and fitted this into the tower bolts for one of the front shock absorbers. There is enough thread on the bolts to accomodate a 1/8" bracket without making new holes etc. The trickle charge is permanently wired to the battery with eye terminals rather than the usual alligator clamps. The 230V (NZ) end of the triclke charger has a short lead about 12" long with a standard plug. In the garage ceiling i removed the single socket which provided power to the tilta door and replaced it with a double socket. I then fitted a short power lead which runs through a pulley arrangement that allows the lead to extend out under the bonnet (Hood) and connect with the trickle charge when the car is not being used. When I want to use the car I disconnect the short power lead from the charger plug and pull the pulley arrangement so that the short lead end comes up out of the way of the Hood. The main reason I did this was I got sick of tripping over a power lead running on the floor.
An added and unexpected benefit is the suspended lead acts as a marker, to aim for, when I am driving the car into the garage. When the bottom of the lead touches the windscreen I am the right amount into the garage.