Mine's just started slipping. I have it on a higher setting as I'm tall-ish, and just now on a 5 minute walk, it slipped about 7 times.
I rang the shop and they reckon it might have some damage inside - the thing is nothing's happened to it, I've only used it a few times so am rather worried it'll prove to be a weak point when my child is heavier (only a baby at present).
Has anyone else had this problem?