Trust for a minor

I am trustee for a Will Trust. The beneficiaries are 18 and 16, held until they are 30 with a general discretion.

The mother is very demanding wanting information about the trust, how much is available and providing lists of expenditure she would like the trustees to approve for tutoring costs, horsing riding lessons etc.

How much disclosure are we required to give to the mother for the trust for the under 18 minor, she is asking for the value of the trust etc.