We had a dog crate made for our last car a Skoda Octavia Estate by Llyntran but we have decided this time to have the rear seats covered and then use a harness fitting into the seatbelt as there is nt as much room in the boot and I also have to fit my full size spare wheel in my boot.
They are a good idea. Some years age when we swapped our Cavalier for an Astra Estate I had a cage made that fitted half the width of the load space. Our dog, a 42Lb Alsatian/Collie had figured out how to get the seats down with a dog guard fitted and had licked the rear window so much the heating elements no longer worked. She absolutely loved it so much so that I had to hold her back when opening up the door. It also meant we were a lot safer in the car all-round.