You haven't responded to me, so I will give you a general answer to your specific question. If you have more specific information to add, please do.
The marital home will be seen as a joint asset in the divorce, which means it, along with other assets accrued during the marriage (savings, pensions etc.) will all be open to be shared in the financial settlement. Finances are only resolved after the conditional order is made (used to be decree nisi) and will not take effect until the final order (decree absolute) is pronounced.
Until you each have full disclosure it is impossible to say what the potential outcome will be, but as stated above, the starting point for a long marriage is 50/50. There is no magic formula to use, just the law in s25 and the judge’s absolute discretion on the final decision based on that law.
Find a mediator: www.familymediationcouncil.org.uk
Section 25: https://www.legislation.gov.uk/ukpga/1973/18/section/25/1997-06-19?timeline=true
Form A: https://www.gov.uk/government/publications/form-a-notice-of-intention-to-proceed-with-an-application-for-a-financial-order
Form E: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/953463/form-e-eng.pdf
Find a solicitor: solicitors.lawsociety.org.uk