The Directory of Grant Making Trusts 20267/27 provides key information on over 2,000 grant-makers, each capable of giving at least £50,000 per year.
Your grants fundraiser really needs access to this information, and you can find out more at https://www.dsc.org.uk/publication/the-directory-of-grant-making-trusts-2026-27/.
The Directory of Social Change has electronic options too, plus a wide range of great resources for charity fundraising and governance.