Happyfarm* court will promote access at all costs, but not if the child doesn't want it. Maybe she's already of an age to refuse to see him?
I'd keep reminding her that she has choices, you'll back her up where her choices are reasonable, even if you don't like those choices (so teaching her that "reasonable" does not equal "what the other person wants"), and that not wanting to visit someone who scares you is totally reasonable.
Remind her there's a court order stating he has access, but that access is supposed to be for her benefit, not his. Keep her focused on the fact she has choices in life, including who to have in her life and how often to see them. He's filling her head with shit, you need to counteract it with information on healthy relationships.
Get her to do the Women's Aid freedom program as soon as she's old enough to be accepted onto it, do it with her maybe. Explain that your marriage to your ex was an unhealthy one and you don't want her ending up with a toxic boyfriend whenever she starts dating.
She's being trained to accept an unhealthy relationship (by her father) and believe she has to do what others want as a priority over what she wants, but you can offer counter training in recognising what an unhealthy relationship looks like and how she has autonomy over herself and her life. It also shows her she can come to you with problems and you'll be reasonable about it not judgemental.
One day she'll hopefully decide to leave him behind, the more training she has about right versus wrong the sooner that day will come. She must be around 12 now if starting secondary school. I've never once heard of a 14yr old forced to visit a parent they don't want to, unless it's the other parent colluding in forcing them to go (maybe because they like the break that part time parenting affords them).
Keep reassuring her that she can't be forced to go to a school she can't even get to and by a parent she spends 4 nights a month with. Counteract his nonsense with logic. Be visibly on her side, not on the fence, that's how she'll learn to trust that it's possible to stand up to people like him.
If he does persuade his girlfriend to move area that might even work in your favour because will he really be arsed to come collect her for his time with her? Also she'll maybe be too scared to want to be there on a Sunday in fear he'll try to make her change schools on the Monday. Just keep reminding her he's got the right to move wherever he and his girlfriend choose to move to, because that's their business, and she's got the right to her own opinions about it and to decide if she wants to visit them where they live or not.
Abusive people like him will be making her subconsciously think she has no rights, just keep reminding her of the rights she does have, even as a child, whenever a suitable situation crops up in conversation to highlight it and keep telling her you'll back up whatever reasonable decisions she makes. That's a better use of your time and energy than trying to make him see sense. He's a lost cause, she isn't.
It's growing up with no proper idea of right and wrong, no real idea of what is reasonable or not and believing, subconsciously so without questioning it, that you have to do what other people want even when it's to your own detriment - that's what fucks up a person and leads them into abusive romantic relationships and toxic user friendships, as well as being under an abusive parent's thumb. Give her the knowledge of her own power, even if she lacks the confidence to exercise it yet.
If she tests her newfound sense of power out on you (the safe parent), don't stamp her down by saying she can't. eg threatening to go live with him during an argument - either say nothing if she's letting off steam or if she's serious just say ok if that's her choice you'll accept it, because it's reasonable if she wants to try living with her other parent, but you love her and don't want to lose her and she's welcome to come back any time she wants to visit or to live if she changes her mind, including if she changes her mind before she's even gone. It's unlikely she'll ever do that if she's scared of him, but knowing that you'll accept her reasonable choices even though it hurts you to do so, will give her immense confidence to go out into the world and live her own life in future without being cowed by others. Whilst knowing that she always has the security of you to fall back on.
That's my take on it anyway.