After having worked as an industrial archaeologist for the Department of Environment Northern Ireland on the West Belfast textile mills survey, from 1991-3 Colin was director of the Royal Irish Academy's Industrial Archaeological survey of Cork City and its Environs (1991-3), the first such study to be conducted in the state. Colin took up a post as a lecturer in the Department of Archaeology in University College Cork in 2000. At UCC, he was involved in setting up a successful master's programme in Museum Studies, and also creating the Historic Building Survey Unit within the Department of Archaeology in 2001, acting as its director up to 2025.

Since 2001, the unit has completed a large number of post-medieval building surveys/conservation studies, regularly cooperating with Southgate Associates over the last 20 years.

Colin is the author of 12 books, which include the award-winning textbook on Irish industrial archaeology, Industrial Ireland 1750-1930: an archaeology (2006, reissued in paperback in 2015). As Colin reaches retirement from UCC, he shall concentrate his future consultancy work within Southgate Associates.