The other thing DP actually didn't mind that one of the mums at kinder has is the Honda Odyssey (i think).
They actually look ok and this woman uses it for her 4 kids every day.
Not high off the ground and they don't look huge, qould be no bigger than an average sedan

ETA: had a quick look at the prius and it has the same middle seat as the kluger in the 2nd row, it's not really a full sized seat so you would be hard pressed to fit 3 full sized car seats in there.
We can JUST fit 2 maxi-riders and HotI's spare THIN seat in the middle when we need a 3rd - i can't imagine the prius being any wider than a kluger so thats something you would need to check also.