Be as prepared as you can be beforehand, it will help you literally and mentally.
Print out all paperwork, so you have it to hand.
File everything in a binder with tabs to separate, so for example if you have a report of the annual statement of his company from Company's House, print that out and put them in date order in one section.
Any correspondence from him that's pertinent include that (for an example an email that says "I'll send you £X when I close this next deal" or "I just bought myself a nice Rolex", or "I agree James needs extra tuition, book him in and I'll send you half the cost")
Evidence of spending above his claimed salary (Instagram pics of him on expensive holidays, ownership of expensive cars etc)
Evidence of his salary from when you were together and why you have no reason to believe it's decreased.
The cost of his current house, be it rented or purchased from Right Move or similar.
Do a front sheet of all the main bullet points.
Kids ages, date that you split up, total that he's paid so far, total owed.
Include things like:
"Mr X says he earns £15k per year, but currently rents a flat in a block which charges £2k to £2.5k per month, so he's able to afford £24-£30k a year in rent before bills, which doesn't align with his salary."
"Mr X has been to New York, Barbados, Australia and Singapore this year on holidays, as evidenced by his social media. His job does not require any foreign travel."
And so on.
Ask for a screen in the hearing room between you and him, hopefully this will be provided and will prevent him from staring you down.
Good luck.