You sound like you have taken the emotion out of it which is good, because any court considers finances and nothing else.
You sound like you've done the maths already, but do include all assets in your maths, pensions, savings, investments, furnishings, car and see if you can agree is percentage split, so you can show to the other party that with the lump sum you give them by buying out, that they get their agreed percentage.
Are you using a mediator, as a mediator would be more experienced in knowing all previous scenarios they have been involved in and possible financial splits, to make both sides "fairly" happy with their lot. And this usually means neither gets exactly what they want but near enough to be able to settle without having to take the case to court and a judge making decisions on your lives.
Your big issue right now is ensuring your current provider will allow you to take on the mortgage on your own. Mine refused to offer me any mortgage whatsoever, despite the fact I'd paid off a 25 year mortgage in full in 18 years and that the mortgage was actually 2k in credit! New rules meant instead of just removing one name, I had to go through the process of mortgaging as a new lender which disqualified me due to a petty rule despite the mortgage broker knowing I was the least likely person to ever default. My only way around this was to take a few personal loans out, I hope you manage to re-mortgage under sole name.