The Leverhulme Trust does not currently (07/06/2023) require its grantees to make their publications open access.
Paying for Leverhulme journal article publication
Does the Trust fund the cost of open access publishing?
"Yes, this is a permissible cost and should be included either within the 25% associated costs allowable on Research Project Grants and Research Programme Grants or within the research expenses category for fellowships. However, open access charges should only be incurred during the period of a Leverhulme award (rather than being built into a budget but with anticipated expenditure after the research and award has concluded). If these costs are not incurred during the life of the grant, the funds cannot be switched to any other budget heading, and must be returned to the Trust.