CETV v Equity

Wondered if anyone on here has been through similar, or can offer advice.

Looking like we will have to go to court, and worried about the costs potentially upcoming, especially if we have to get an Actuary report.

Married 15yrs, together 22. Kids over 18. Separated 2020.
Stbx earns 30k
I earn 45k NHS pension. Partner earns 30k, she has 1 child.
I can take early retirement next year at 52 yrs old.
My CETV is 450k
Stbx CETV 21k
Equity in house is £290k
Ex will not negotiate, they want the house (4b detached house) and a cash lump sum payment to make it equal.

I can't do this, as I don't have the cash to. I'd like 50/50 split of each, or 60/40 to them, but they won't budge. For some reason they don't want a pension share.
I will get a small lump sum when I take early retirement, about £49k, but I have joint debts I've been left with, and I'd like to buy into my partners home. As I'd like to try to get back on the property ladder again.
I've offered her up to 80% equity and 20% my pension, but it just keeps getting declined, and they say my offers are tedious and I'm wasting their time.
I don't want her to have to sell the house, but if we go to court, could that be an option?
How can I try to negotiate more, to try and save costs?

If you haven’t got the cash she can’t have it.
House could well be sold if you can’t afford to keep it as she only needs one bed and is living in a four bed.
Presumably she pays all the bills at the FMH and has done for some time?
Does she have the means to give you £145k equity in exchange for half the pension that she won’t be able to access for some years?