Maximising a crowdfunding campaign

I am about to launch a Sponsume appeal to raise funds for a theatre production on the London Fringe. I need help in targeting potential donors (beyond my immediate circle). The play is about the rediscovery of folk music at the start of the C20th , and so interested groups may include London-based folk and classical music groups? I need expert help in finding and targeting potential donors (beyond my immediate circle) to whom I could send the Sponsume video.