Thanks so much for your replies! It is amazing how just reading your replies has made me think about the whole situation in a different way.

Her school does have a Chaplain - I might look into meeting with her and having a chat about it all. Other than that I can't really think of anyone except for me that she would open up to.

I have definitely thought about the impact that all these huge changes in her life is going to have on her. I can't imagine it not having an impact - I just wish she would lash out the way she is because I am finding it harder and harder to react in a calm way when she is so aggressive towards people, especially me. Now that I am thinking about it though she really needs a supportive reaction that she can predict to make her feel safe - and going on from that, my routines around the house have become less stable over the school holidays and I should really get them back into place to help with that.

I have talked to her Dad again and we have decided that I will pick her up this afternoon from school and then have a talk to her about maybe meeting him at a park for a play instead of her going to his house for the afternoon. If she doesn't want to though he seems OK with leaving it at that - and letting her come around over time instead of forcing the issue - I'm really not comfortable with forcing her but I am not sure letting her make the decision is the right thing either.

It breaks my heart so much thinking that she isn't getting the love and support she needs right now.

Thanks so much for the comments - they have really helped!!!