Ashton was in BBH fitteds from birth (5kg). Have you got it on the newborn fold? This is where I went wrong because I was just doing it up on the tightest snaps without turning the front down!

To the bubba with the rash (sorry trying to be super quick) try no detergents at all, ditch the baby wipes, they make Ash rash up BAD, and use face washers that are just wet with warm water.