Thanks Andie & Trish.

Barb, he's feeding 8-9 times in 24 hours, cluster feeds in the afternoon/evening. I feel comfortable with positioning and attachment and change his nappy either before a feed or in between when swapping breasts. I notice his tummy makes a lot of gurgling noises so maybe it is that and him trying to poop like you say. My main worry about everything is if he's getting enough because while he is consistently gaining weight, his gains have been low (around 75grams a week). However, he has grown in head size and length and seems healthy otherwise.

Thanks again for your advice ladies.