I have to ring school and tell them so they can decide what to do. I only know the girls first name but its quite uncommon so I think they'll work out who it is.
But if I ring the head of year and say I don't want the girl to know its come from me/dd will they respect that? I don't want the girl getting cross with dd. there's quite a few girls who know about it apparently so the girl won't know it must have come from dd.
Its a child protection issue. You will have flagged it, and won't get any feedback from school. You are doing the right thing. You don't need to tell your dd you have called. If she is telling several girls then clearly she is asking for help. If it would make you feel more secure, then call NSPCC. School and unusual name will do the job. As will as call to social services. You can't rescue every child who is abused, but you can do what you can for those whom you come across.
Yes! It is called "safeguarding" all organisations dealing with children and/ or vulnerable people, have to have a policy and a person overseeing it. All teachers have to have (yearly) training on safeguarding.
All schools will have a Child Protection Officer who will know how to deal with this. Anything you say will be confidential - and it might well be there are family issues anyway, but the more information he/she has the more something is likely to get done. If you have any further concerns, then I'd follow them up again with the CPO and then perhaps contact another authority as well - police, social services, NSPCC.
If you can't speak to the CPO easily, ie due to illness, the next port of call will be the Headmaster. I work at a school and if our CPO happened to be out, we have instructions as to who else to speak to.