You could get your lawyer to write a letter stating that he/she has been given instructions to subpoena his financial records…the threat might be enough for him to disclose but if you actually have to issue a subpoena, it’ll cost you financially. The only way you’ll recover costs that have been incurred as a result of his non-disclosure is before a judge who issues him with a “costs order” (order to pay the costs you’ve incurred as a result of his non-disclosure). Unfortunately, non-disclosure is a common occurrence in property cases and I would argue, a form of financial abuse that perpetrators are rarely held accountable for because they end up settling before it gets before a judge whilst you’re still left with the costs incurred. Your lawyer should be able to give you info re cost of going to Court, approx time frames etc.
Look up “legal barriers to economic equality after family violence”. It’ll link you to a relevant paper from Women’s Legal Service and you might get some ideas

I’m in the same position, separated almost 18 months ago. Ex Ignored 3 letters from my lawyer.., so the next step was go to court.., mean while the value of the property has increased 10% in 12 months..which I’d like to buy his share…, it’s FINANCIAL ABUSE at its finest
Ex, hasn’t contributed financially . I have 100% care of two young children, I’m working casual to help pay the joint mortgage and related expenses so we don’t end up homeless. Meanwhile he has repartened, has a capacity to earn $130k pa, and pays $1 day child support, with a CS dept $15k. I can’t afford to go to court!…,
Any ideas 🤷🏻‍♀️🥲 I don’t have the time or energy to deal with such a childish looser! I think I’ll just continue on my merry way…