I was of the understanding that this is 'caselaw' & therefore enshrines the current position.
This right here is why you should not get your legal advice from the internet. Someone has an 'understanding' and knows a couple of words, but has no real idea of the nuances.
OP, talk to your solicitor, listen to your solicitor, bear in mind that the solicitor is going to get paid regardless, also bear in mind that you don't have to have a "high chance" of winning for a solicitor to be willing to take you on. You need "a chance". As someone mentioned up thread, find out how much you may already be on the hook for because of the caveat.
As you are hellbent on doing this, you might want to consider starting to save hard so that you can be ready for a possible costs order to avoid bankruptcy. What is your plan if you do get cleaned out, made bankrupt and then can't rent somewhere? You have kids, you need to think long term.
There is no guarantee even if you 'win' (and that word carries all kinds of varied meanings in the legal context) that you will get your costs out of the estate.
I think you mentioned upthread that the estate was worth under 600k? I have recently sat in a court room, where the combined costs of all of the barristers and instructing solicitors were in excess of 500k. It is unlikely you will get to those kind of numbers (this was a much bigger estate), but not impossible if the other side hires 'the best' and you lose and they are awarded costs on an indemnity basis. You also need to be aware that fights over costs can drag on and generate more costs.
Even be careful if you get a solicitor on a 'no win, no fee' basis. Barristers are rarely willing to work on this basis and it usually excludes disbursements etc.