my 10 and half month old has been in size 4 nappies a while now but he started leaking and poo exploding out so went up to size 5 however it seems like he is also leaking with these too as went out for a couple of hours and got back he was wet not had a poo yet though only started the size 5 last night so not even been 24 hours yet size 5 seems massive on him ....what should i do keep to size 5 or go back to size 4 even though poo explodes out sides etc?