Maccie, I think you are missing the point I have made about Article 8.
the blood tie is simply not important when considering what makes a family relationship - or at least it isn't in the eyes of the ECHR which is the ultimate legal authority the UK courts have to consider.
What makes a 'family life' worthy of legal and social protection is the emotional/social bonds that build up over many years. Whatever the op thinks about this SF - and she clearly dislikes him intensely which the child MUST be aware of - he has been in her life since she was 2 years old. She is now nearly 15 (sorry I got the age wrong, I note she is not 15 until July, but she is still very clearly in the Gillick competent territory).
If she has 'previously disclosed' abuse, she doesn't appear to be willing now to repeat those allegations, so there is very little any state agency can do to 'protect' her, absent compelling evidence from another source.
This shouldn't ever be about 'choices' . a child should be free to have a normal, healthy relationship with ALL the adults who take part in looking after him/her. It is sadly usually only ever the adults who fuck this up for the child by acting out their own dysfunction and emotional immaturity. I don't think it helps by adding a layer of legal process on top of such an awful situation.
But I accept, I don't have any answers other than to try to avoid letting this kind of situation brew in the first place, which I can see is a)not helpful and b) probably not possible if you are dealing with someone v unreasonable from the get go.