He was Regional Bishop of Saldanha Bay in the Diocese of Cape Town from 2002 to 2003, having served as Dean of Kimberley and Rector of St Cyprian's Cathedral from 1992 to 2002.
His second wife and widow is Sarah Rowland Jones, a fellow priest who then fulfilled a research ministry in the Anglican Church of Southern Africa at the behest of two successive Archbishops of Cape Town before returning to Wales in late 2013.
Projects initiated by Marcus in Kimberley included the establishment of a ‘Tamar House’ place of safety for abused women and Rape Crisis Centre and an Ecubread feeding scheme for the homeless.
Adding to the fabric of the cathedral, stained glass by Estelle Valle was installed in the remaining clerestory windows in the sanctuary and nave, and the Stations of the Cross carved in wood by Bill Davis were introduced to the outer walls of the north and south aisles.
Marcus was renowned for his insightful weekly commentaries in the cathedral pew leaflet, sometimes also published in the local press.
Bishop Tom Stanage presided at a Requiem Mass at St Cyprian's Cathedral, Kimberley, 10 December 2003.