I’m a member of several co-operative consortia or secondary co-ops - these being the terms we use for for co-operatives of other organisations (often themselves co-ops).
Co-op Culture is a Company Limited by Guarantee (CLG) registered with an adaption of Radical Routes model
Platform 6 is a Company Limited by Guarantee (CLG) registered with an adaption of Radical Routes model. Currently looking to convert to a Co-operative Society (a relatively simple process) for various reasons including the ability of the Co-operative Society model to have member share capital. They are also waiting for the registration of a Sociocratic Co-operative Society Model with the FCA.
Co-operatives UK is a Co-operative Society and a kosher secondary co-operative being a co-op of co-ops.
Re the choice, it is 6 of one and half a dozen of the other.
Company form is better understood by other stakeholders, but society form is not much of a problem - few niggles like HMRC systems/forms are set up for companies.
Societies can have member share capital, and raise finance from the public without much of the expensive regulation around doing so.
Co-operative Societies can pay a dividend to members in proportion to their trade with the co-op. Useful for equitable distribution of surplus and paid before corporation tax (CT).
Co-operative Societies may find it easier than companies to get mutual trading status (MTS - exemption from CT) on the basis that they are merely a vehicle for their members to deliver their services and those members will pay tax on their own surplus. Companies are not barred from MTS but the Society form has a big history in these cases.
Companies are easier to carpet-bag or demutualise, indeed the conversion of a Society to a Company would often be the pre-cursor to demutualisation.
Companies can be formed slightly more quickly (one week vs. 3 weeks) and the rices are the same if you go through Co-operatives UK (approx £150).
Companies are easier to register with significant changes from the off the peg model documents - Companies House isn’t bothered while FCA will check.
Whichever legal form you use then you can structure your governance internally as you see fit, amend the governing document for free etc.
I commonly advise organisations who are struggling with the choice to set up a CLG as it can easily be converted down the line.
You can download the guide I created for the Transition Network from my buymeacoffee page: