It went well, thank you :) It was only a preliminary hearing and I didn't have to talk, but ex was there and that's never pleasant. Ex sent a statement that denies everything, even things he admitted before to SS and the GP 
, so I think the case looks quite good. Or at least he and his statement look very unreliable.
My lawyer explained a bit more about what kind of proof the judge needs to make her/his decision (sorry MotherofDragon if someone has explained this to you already, but I thought it might be useful information).
Since it is not criminal court the judge does not need to believe your allegations are true 'beyond reasonable doubt', but simply be sure 51%. Hearsay is allowed, so if you have a witness who saw or heard him do something that you accuse him of, that counts as proof. And if you have proof of certain incidents, the judge can use that to make up her/his mind about who is right about the risk to the children, even if you don't have proof for the whole picture of the relationship and his personality. S/he will also take into account how convincing you are when you are talking during the fact-finding hearing.
So I think with your statements, screen shots, medical records and clear and emotional statement, your case looks good too, MotherofDragon.
I was very scared this morning, triggered, but had a session with my therapist and some nice chat with my lawyer about the children and holiday, and by the time I was in court I was quite calm. In court I just kept staring out the window so I didn't have to look at him.
As my therapist said: these things are scary because you don't know what will happen, but once you're in the situation they often feel quite normal. And that's how it was.
You said you will have someone with you. Will they be there the whole day? I think it's really good if they could keep you entertained and grounded while keeping an eye on the legal proceedings, so you can focus on yourself and your statement.