It does sound very confusing and I seem to remember you already emailed asking for clarification and didn't get an answer in that respect. I can only assume that the Judge is going to decide on the allegations and rely on oral submissions on the day, but it does seem wrong that you don't have the opportunity to respond to the allegations with evidence, before the hearing.
Could you get a half hour's free legal advice on this? Try two or three solicitors - some are better than others. It's a really difficult situation to handle on your own and I don't understand this one either. How can it be a composite fact find and final hearing, when you haven't been given the opportunity to formally respond to the allegations before the hearing.
The only other thing I can think is that you just let this hearing go ahead, having submitted additional evidence after seeing her allegations, and if it goes badly, appeal it - you would have grounds for appeal if you hadn't been given the opportunity to respond to allegations. At an appeal you'd get a more senior Judge. I'd be prepared to appeal it anyway, and be prepared to ask for permission to appeal at the end of the hearing (if it's a Judge and not magistrates). You need that permission out of the way before you can submit an appeal, to avoid delays.