Story Tent is rooted in conversations with the Cambridge Interfaith Forum back in 2013. They have an interesting article on their blog about the project - follow this link. It explains more about Scriptural Reasoning and its connections with the Story Tent concept.
One of the sponsors of the Story Tent curriculum development is the Westhill Trust. Here is a link to an article on the Story Tent hosted on their website - along with many other interesting details on the Westhill Trust iteself.
Rose Castle themselves have a great website, including a page on the Story Tent Project - you can read it at this link.