My mum has a Hyundai Kona, which quite easily fits a folding scooter in the boot and room for shopping bags ontop!
I believe, you are on your own, so you don’t need nothing too big and if necessary you could always fold all or part of the rear seats down, which would give more than enough room. If the chair will go in sideways strapped agains’t the rear seats, it gives a bit of room in front for shopping bags.
Nissan Qashqai, Renault Austral or even another Juke/Toyota CHR with the rear seat possibly folded.