To OP
Form E requires 12 months of Bank Statements unless that has changed since my Divorce in 2016. However, Courts can at their discretion order at the FDA for documents that go further back than 12 months.
If your Ex has planned the Divorce in advance he may already have disposed of assets without your knowledge. I am not a family solicitor or Barrister, but remember during my own Divorce that assets disposed (by setting up Trusts for example) of within 3 years before the Divorce Application could be re-visited and taken into account if the Courts considered that such disposal was for the purpose of frustrating the other partner's entitlement. If necessary Trusts can be set aside by the Courts. Same with any unusual large sums of money that can't be accounted for.
The switch from Self Employed to Limited Company would have to be explained by your Ex. However, it is possible that his clients prefer that he operates as a Limited Company?
For a newly formed Ltd Company it may be a while before Accounts are produced, but courts can make reasonable assumptions as to what the; total revenue will be, what are legitimate costs, taxes due and what is left over that can be distributed in Dividends.
As for not paying out the full amount of Dividends possible and leaving money in the Company for a rainy day that will depend on the nature of the business your Ex is involved. Legal opinion is required on that point.
If you know the name of the Ltd Company you can check online with Companies House to see who is named as Director. Possible he may list a new partner or even a relative as a Director so that they can receive Dividends, but in reality they are passed on to your Ex.
Both you and your Ex will be required to complete a Form E accurately an truthfully. However, if you think you Ex's Form E is missing information it will be up to you to provide some evidence. This is where a solicitor (or a Barrister if you are talking big sums) will be needed as they should be familiar with all the tricks people have tried in the past.
As for being able to afford representation you may be eligible for help from your Ex if he is earning more than you and has greater assets. Legal Service Order I think it is called. Any help you receive from Ex will be taken into account when settlement is made.
Might sound odd that one partner pays the other's legal costs, but logic is that if both partners have good representation the proceedings and settlement take less time to resolve and total legal costs are less.
Good luck