I don't have experience of changing schools, but I wouldn't worry too much - a new school will want to form their own view of her. Resources for SN etc are sufficiently limited that noone will want to carry on with a "label" just for the sake of it iyswim. Also in a sizeable primary school there are highly likely to be kids with language problems, and other relatively mild SN at the very least, so your DD wouldn't be particularly unusual if she does have some continued involvement with senco etc.