I got a Gr8 expectations backpack duo which is really good. Bottom compartment fits in 4 MCN + covers. Front compartment holds wetbag. Main compartment fits multiple changes of clothes, 2 net pockets fits babylegs / socks / shoes / hat / spare formulae. And insulated side pocket for a bottle or some water.

The smaller bag is great for shopping centres, I put just a wetbag in it and a nappy and go back to the car to refill...