My ds is 13 weeks though was 5 weeks early. He has been bf but from 3 weeks we have been trying to give him a bottle of bm. He will take it for a day or two and then refuse. He has had 2 or 3 feeds of formula but refuses them very quickly and wont take a full feed. I have tried different flow teats but am using avent bottles. Any tips would be great as i would like him to end up with 1 formula feed a day and to know i can leave him if need with dh.