I had the privilege to attempt to play this lovely arrangement for theremin and organ
Originally written for organ solo, the composer, Graham Twist, expanded the idea to include a theremin part which I think really suits it. In the video description you will find a link to Graham's organ solo performance, where he also includes his contact information if you would like to request a copy of the score.
https://www.youtube.com/watch?v=aHPFaVABE-k