From their website ...
Launched nationally in November 2017, the fully-revised and expanded Crossing the Threshold toolkit offers a step-by-step guide to managing a church building project. First created by the Diocese of Hereford in 2009, and subsequently updated in 2013, this newly updated resource is packed with 268 pages of advice, hints and tips for any group taking a community development approach towards adapting a church building for wider community use, while balancing the needs of existing worshippers.
You can access the full toolkit from the Diocese of Herefore here