Have you tried letting her latch on directly again recently. Now she is older she may have more neck strength to do so. I used them for about 2 weeks with ds, coudlntl be bothered to get up to fetch them one night and hey presto, alternative is to try once she has had an initial feeding frenzy and is more relaxed . They aren't as efficient at allowing the baby to feed until satisfied ( tire before they get a really good fill) and can inhibit production as it is the suck which stimulates it, so she may get frustrated. At this stage there needn't be any real confusion of textures.

Babe is 13 weeks
We have used avent standard nipple guards from start as she had trouble latching on. I gave up trying to get her to latch to my natural nipple as we bottle feed twice a day and I thought the textures would be too extreme. (dunno if I made a mistake there but anyway). ..
Last two weeks I've had a real battle feeding during the day. I think babe is easily distracted and sometimes have to resort to putting a muslin over our heads. I now understand from a mother baby group that this is normal, however I also wonder if babe is getting anoyed with the nipple guard.
Are there enough holes now that she's bigger?
Is the width too big, when compared to bottle top?
Could the guard be touching and anoying her gums (she is teething)?
I don't want to give up breast feeding yet but am currently expressing then bottle feeding as she is less distressed this way.
Any advice anyone?

Many thanks