Next Left has a good appreciation of him by Stuart White:
Colin really stood at the confluence of two traditions (as did the post-war Freedom group more generally). On the one hand, he was of course shaped profoundly by the theoretical tradition of anarchism. He knew his anarchist classics - especially Kropotkin's Fields, Factories and Workshops - and he drew on them.
On the other, Colin was also animated by the diffuse traditions of working-class and popular self-help - resolutely practical traditions concerned to get things done, to make the world better in some simple but important and measurable way, and which have little time for theoretical niceties. He sought to bring the traditions into dialogue, for their mutual benefit.