The financial separation aka the financial consent order...
You both agree in principle how you're going to separate everything. Theres basically 2 ways.....basic disclosure (form D81) or full disclosure (the dreaded form E).
I can only talk about my experience of the easy D81 way. Form E was about 35 sides of paper and needed bank statements, supporting evidence, pension actuaries, blah blah, nearly made my head explode and I still get cold sweats just thinking about it 2 years later!! As you have some chunky looking assets, pension and properties you'll probably be best going down form E route and paying a solicitor as much as they want to take this nasty nasty bit of the process off your hands.
You fill in the form with all your assests, debts etc which is HOW THINGS STAND BETWEEN YOU AT THE MOMENT. This is sent to the court with a very formally worded document (the draft consent order).
You pay a solicitor to draw up a draft consent order (because remember, its only a draft and not official until the courts agree it) which is very wordy document full of legal jargon and thee's and thou's, and subsection 42 paragraph b, ii type gubbins. You won't stand a cat in hells chance of writing this yourself so don't even try. Its REALLY important that you get make sure there is a "clean break" clause included in this document, because thats the bit that blocks your ex from coming after you in 20 years time if you win the lottery or have a business which does massively well in the future.
The soluctors sends the draft consent order off the court for the judge to consider it and stamp it (seal it) as approved. Judge might decide he (or she!) wants some further answers or explanation of why you've decided on a certain split. This will sometimes be done in writing via solicitor to the judge, or you might have to go to a hearing in person where you'd both be questioned on it.
Consent orders can include child maintenance agreements (which bizarrely can be overuled after 12 months if either of you decide to!), Spousal maintenance (increasingly unusual), or conditions like selling the family home asap or waiting until youngest child turns 18 (mesher order, also increaingly unusual).
The divorce bit of the whole process is MUCH easier to navigate than the financials. Especially is your ex is going to be a dick about it. Maybe try the divorce yourself and just pay lawyers to do the finance bit?
(Please don't rely on ANY of the above, check it all out yourself and read up. I'd hate to have forgotten something vital!)