Wife earns double, what’s a fair settlement?

Using the Divorce Calculator I get a 60:40 split in my favour. My wife has suggested a 50:50 split. I would welcome any opinions on what is fair based on the following:

Married May 1995, Separated September 2017, Decree Nisi set for 20 February 2020
No children.
Me age 51, wife 46
Wife earns circa £75K
I can potentially earn circa £36K(self employed)
Wife pension £40K
Me no pension but savings of £30K
All personal possessions are roughly equal (cars, valuables, furniture)
House value £410K, mortgage £40K

I can’t afford/ am not able to get a mortgage big enough to buy her out(she rents a flat elsewhere). We are both happy to sell and divide the equity. She has a much higher mortgage potential than me (last three years accounts are roughly £24Kpa for me) so I feel a 60:40 equity split is fair. I would have a higher cash amount for a deposit compensating for the lower mortgage I can get, giving a fairly equal housing standard for both. I would very much welcome any opinions on what is a fair split of the equity.