Siôn is a member of Calverts, the London branding, design and print co-operative, and a co-op business adviser with Principle Six, a development partnership focusing particularly on workers’ and community co-operatives.

He is a trustee board member of Community and Co-operative Finance; a founder member of the Worker Co-operative Solidarity Fund; and an elected member of the Worker Co-operative Council.

Siôn has also served as a director of Co-operatives UK. He is active in Co-operatives London, the network for all kinds of co-ops in the capital.