I’ve got a C-max. Bonus over an estate is there’s masses of headroom for getting changed. With the rear seats removed I can sleep on a roll mat in the back with 2 bikes (big water carrier stored behind the driver seat is the same level as the boot floor so makes it flat).
TBH though the best setup is a 2-person pop up tent from decathlon for £45, park car, tent up in well under a minute, and all my camping kit lives in a duffbag, throw that in the tent and I’m ready for the night. It’s probably quicker than clearing a sleeping space in the back!
It’s quick enough to pitch and pack away again that you can park up somehwere discreetly, sleep, then have the tent packed away before breakfast. “What do you mean Mr NT Warden? The sign clearly says no camping, not no eating breakfast next to your car!”
Or (never tried this), but you can get roofbar mounted tents for landrovers whichhave a matress in the base. Obviously requires the cars roof bars to be able to suppourt 2 people + tent through.