Mortgage advice

I currently own my home outright on paper original house price was 280k back in 2021. Revalued other month for 315-330k.
Funds were from a life insurance policy from my father passing my mum gave 280 to me as an early inheritance however I wanted to pay her back so set up a loan agreement at 1.06k a month for 22 years.
I’m now married and would like to remortgage off my house to pay my mum back in full so wife and my self can have a normal mortgage.
However I’m struggling to find a lender for such a specific loan and paying the money from the loan to a family member. Best deal I got was a 10 year duration which was not overly helpful.

Any advice would be much help!

I earn 70k self employed 4 years worth of good books growing 10k a year profit. 29 male
Wife is 28 earning 52k employed