Thanks for the advice I'd heard they can forget how to latch, but she
hasn't missed days which is what puzzles me.

Don't quote me on this, but doesn't the palate change shape over time,
breastfeeding helps it develop to the correct shape (as well as getting
the correct muscles working), but ultimately it becomes too shallow to
latch well to breastfeed, so it's not so much the child forgetting, but
growing out of the ability to do it. There is a book called something
like "how weaning happens", it may be a LLL book, anyway, from what I've
heard it is pointed at child led, or at least compromise, rather than
this is how to get your baby off the breast at precisely age one!

cheers
Anne