Making legally binding agreement without solicitor

[Scot22]

A neighbour wishes to make an alteration to his property. It may have an impact on mine. He is willing to accept current and future liability if any costs may be incurred by me.

I would not be happy with verbal agreement. Can you make a watertight document which would be legally binding without involving a solicitor and associated costs ?

[echat11]

Posted for info only - https://hallellis.co.uk/contract-law-basics-formation/

[Scot22]

Thanks echat you are always so helpful. I've made it a favourite.