Hi Phoenix, thanks for replying, you've made some really good points. I think I do have oversupply, yes. However this only seems to be at certain times of the day - when I get up to do the night feed and first thing in the morning (6:30-7am) my breasts are very full and hard. I have had plugged ducts and am currently on antibiotics for possible mastitis. The rest of the day my breasts feel "emptier". A does sometimes cough and splutter when feeding during the night and also in the morning. However he otherwise seems happy to feed. I had been expressing first thing in the morning as that seemed to be when my supply was best, but maybe that has caused problems by exacerbating the overproduction at that time?
I had actually started just using one breast per feed over the last couple of days (having previously switched to the second breast when he'd come off the first breast) - now I just keep offering the first breast until he refuses it and actually it does seem to have helped in that he seems more content after a feed and has had longer intervals between feeds.
I think you're right and maybe what I need to do is cut down on the expressing (as that is probably exacerbating the problem) and space it out over the day so that I am expressing just a little each time rather than a lot in one go? I am reluctant to stop expressing altogether as I've found it a lifesaver for my husband to be able to give a bottle when I'm exhausted. I do wonder if I need to do the bedtime 11pm-ish feed myself though because of the melatonin thing as you say - maybe he'd sleep better for the first part of the night if I did that?
Thanks again for the help, I do find myself floundering a bit having never done this before. I haven't found the health visitor especially helpful either. Am going to go to a local breastfeeding support group this week and see if they have any advice.