Thanks for all your brainstorming guys! I think I've come to the conclusion that it must be a fit issue.
She's washed her nappies so many times that I really can't see how it could be that- like you Sam, I'm pretty slack on the whole prewashing thing and it's not been an issues for me. And the leaks are happening pretty much as soon as the nappy is put on, so it's not a time thing.
The only problem is that she lives 2 hours away now so it's impossible for me to see the nappy on.
Unfortunately she says she'll go back to using sposies for at least a few weeks then give them another go.
I'm thinking I'll send her Z's old small thirsties covers, prefolds and some snappis to see if she'd use those over sposies.
Thanks again for all your thoughts.
