I have a three way fridge too, its the Electoulx one, but looks remarkably like the one linked from Ebay, so either the manufacturer has changed or its the same product under a different name.
It doesn't go in the boot of my Impreza (saloon) as the opening is not wide enough, so for Le Mas it sits on the back seat. Used it the other weekend when I took the wife and baby camping (forgot the tent poles but thats another story!). So fridge went on the front seat instead.
It works very well, although we tend to find with 6 of us camping it tends to be quite full of food, with little space for beer! If you don't turn it down overnight it can turn beer icecold!
We tend put a small amount of drink in it and plug it into the car on the way down. Rest of the space is filled with kitchen and eating utensils. Jus means we have something cold to drink when we first arrive.