My thread from last night has disappeared 
Re: my DDs best friend with abusive father.
First i want to say i am so glad i asked for help here and found everyone's input so valuable. Thank you all who posted. I'm posting this as many of you were very concerned and wanted an update.
I did phone the police this morning and an officer came round this afternoon and took a full report. He reasured me that the correct people will be informed and look into this straight away and get help for the child (and her mother). He said they will approach this with great sensitivity and is hopefull that my DD and this girl's close friendship will not be damaged in the fall out. His personal advice was not to tell DD i've made the report.
I felt awful "going behind my DD and her friend's back" - but i know it was for all the right reasons.
Thanks again AIBU ladies.