I have a VW Tiguan. It's a 4x4 SUV with 5 seats and boot no bigger than a hatchback. I can only get the pram in the boot plus some bags. It's still bigger than most 'small SUV' options out there which are literally no bigger than hatchbacks just are higher and bulkier from the outside. But no way I'd have room for another child (it's also me, husband, medium sized dog and baby right now). In my honest opinion you'd need the bigger option SUVs for actually bigger boot space to fit a pram and a dog to free up back seat for second baby. Or a seven seater option. Or an estate car with properly big boot.
I reckon an estate car is quite good for 2 kids and 1 dog or one of those SUVs with a big enough boot for the dog. But if you want more than 2 kids might be worth going for a 7 seater already?
We have not peugeot 3008 ;)