Do I have to let aggressive ex see DD

[Cresida]

My ex partner had threatened me a few times and I have reported him. I don't want him to have any involvement in my daughters life as he has constantly tried to make life difficult for us and hasn't really contributed anything substantial.
If I deny him the right to see her, what could happen?

Document everything and let him take you to court for access if he so chooses.

He could take you to court, only you know if that’s something he will do though

You could refuse and allow him to take you to court for access, which is likely to be granted. Given DV mediation isn’t recommended.
You could offer supervised visits at a contact centre to be paid for by ex.
I recommend that you do everything in writing (text or email) you need to put your dd best interests first so offering contact centre makes you look reasonable.