The cooperative Seed for Change settled in England started to use and promote the decisional consens method and mediation in the far 2000. This is them history.
Really well done their manual and guide about apply the consensu method as decisional tool for group with diversity:
https://www.seedsforchange.org.uk/consensus
Thi image is really usefull because because is explaining the 3 positions of the consensus method during the Orientiring (moment in which the participans expose their agreement, disagreement, consensus and dissensus on a decision):
In their resources:
https://www.seedsforchange.org.uk/consflow
A workflow to explain better the procedure before to try to arrive to consensus that means agreement in disagreement:
