Social Procurement in the UK....who are the main players?

Hi All, I am keen to learn more about the Social Procurement/Supplier Diversity landscape in the UK. In Australia we have: Supply Nation (Indigenous), Social Traders (Social Enterprises), NDS (Disability Suppliers), BCorps, WEConnect (women owned businesses) plus some others. In the UK I have come across: Social Enterprise UK and NMSDC. I am mainly looking at the bodies that certify a particular type of supplier. Am I missing any others? Thanks