It is possible your daughter may disclose some of this in nursery or preschool? They are not allowed to question your little girl but they have to allow her the space to say what is on her mind, if they feel that it is concerning they have a duty to report it.
You could also have a word with your health visitor about the things she says and she may be able to advise you too. I think the thing is that you have to allow your little girl to say these things and get them off her chest and try not to react even though I know it must be really difficult. Get some professional advise as to how best to deal with it and hopefully someone will see that your little girl is being subjected to a form of emotional abuse. Sometimes when they cant get to us they get to our kids x