huge hugs Nicola,
Sounds a lot like Emma in the early days. I was so sure we were dealing with issues related to OAL/OS and her tongue tie daytime (so wind due to not being able to deal with the fast flow and amount of milk) and then FM/HM imbalance as she'd get fed up with one side easily (weak such again due to TT) and I'd swap and swap again and again. In the evenings due to my own exhaustion (wintertime, 2.5 yr old male toddler at home, DH working 12 hr days Mon to Fri so alone all day including bedtimes and an EWing toddler to boot) my milk would actually be very, very low. So I used a bottle for that 7-8pm feed, first to the breast and then I'd top her up with what otherwise I would have used for a DF. It was a sanity saver, really and truly.
From when I first introduced it, I had both of them down by 7pm for sure and had an hour or two of peace for myself. DH would get in around 8pm, cook for us and I'd go to bed. I fed 11pm or 12 midnight DF, DH would do everything but the feeding. I never ever learned (nor did my babies) how to feed lying down. I have teeny boobs and babies with big heads (lol) so I could never see what was going on. I would just prop myself up in bed and snooze sitting/half sitting (which was also good for the OAL as they fed against gravity.
G's weight gain is really brill for a EBF little girl - AMAZING! Also, I wanted to add that I was really trying everything to not go dairy free as it would be extremely difficult in PL as those allergy-products even for gluten free, diabetics etc are only now coming onto the market. We even had green mucousy poos (but they were the FM/HM imbalance type) and with such amazing weight gain, good poops when block fed or fed non-distracted, lack of issues with skin etc - I finally put all her early issues down to TT, windiness associated with this and OAL/OS, distractible nature (and big brother around LOL) and lack of patience in the evening combined with spiritedness and my exhaustion.
I swear until we stopped at 18 mths, Emma's only "textbook" feeds (after a very successful feeding relationship with Oscar) were DFs or early morning feeds later (when I went back to work at 7mths, I would feed her semi comatose in the mornings as I had to leave at 7am). Not great, I know, but I did what I had to to "control" the others - in the dark where possible, in friend's bedrooms when visiting their houses, under a black blanket outdoors etc etc. Otherwise, we had the windy green poops even at 3 mths +.
So, just another take - it can be lactose overload, distractibility etc and not necessarily dairy.
S x