Hi, I'd really appreciate a bit of help on this one, it's difficult because dd is not quite but nearly an adult
DD is 17. Her father has been arrested many times over the years for various horrible things involving children. "Just" 1 caution but currently under 2 investigations, 1 for historical hands on abuse.
Dd has decided she wants nothing to do with him however she doesn't want a big show down, she just wants to get on with her life quietly and without bother. She has changed her name away from his to try and stop people making the association.
He stuck to this for about a year with me giving occasional updates about important things like school results and generally playing nice and being the buffer for her. Eventually he decided he'd waited long enough and started tagging her on Facebook. I politely asked him to stop after finding her sobbing yet again. He did it again so I sent a very strongly worded message saying, basically, back off (possibly a couple of swears in there) He did, removed the latest post and stopped paying maintenance 
Then social services rang to check that dd was not in contact, reiterated that police investigation is still under way and that they still consider him too high risk for contact even considering dds age.
So, today, dd is at work and his sister turned up begging her to forgive him, he's innocent, it's the dirty kids fault not his, come meet his new girlfriend and her dc... poor DD is in absolute bits. Had to explain to her colleagues about the paedophile father, feels unsafe being there etc etc. She was polite to her aunt but really wants it all to stop.
I'm wondering what next, would it be possible to send a solicitor letter to him, his sisters (and cc social services??) just saying she doesn't want contact with any of them virtual or actual at home or in her work place etc and that she will make contact in the future if she changes her mind. Is there any value in this? I don't think she can prove harassment or anything at this stage but she is past herself with the stress and feels they are never going to stop. She's been through enough, I need to help her but I'm at a loss of how to do it without being inflammatory which she doesn't want either!
From a legal perspective does anyone think it's worth the cost of a letter?
Name change as, obviously, hugely outing!