Ok thanks - at least I can eliminate that option from my mind.
I never wash my breast prior to feeding so that isn't the issue. I have tried to give her some water kefir - she doesn't drink that well without the sucking action so it is difficult to get it down. Should I persevere with this? How much? Would powder be better?

You can apply some kefir to the nipple before feeding and maybe stop frequently to apply more.

Would coconut oil be an option? You have mentioned it as a surfactant.

But this would only be a band-aid. With the antibiotics you mentioned it sounds even more like a flora issue. So I would go the kefir route first.

It does seem to be the wind causing pain-so flora seems a reasonable answer to the problem.
She did have a course of oral antibiotics early on and also two intravenous antibiotics injections when she had a fever without focus at 2months old that was causing concern. (I didn't know everything that I know now and was totally freaked by the paediatrician talking about her immunity and health complications!)