Roger joined the 21st Royal North British Fusiliers in 1823 while working as a farm labourer at Askeaton County, Limerick, Ireland. He was stationed at the Isle of Wight, St Vincent in the West Indies, Windsor, Kew, Reading, Winchester, Portsmouth, Ireland, Northampton and Chatham. By 1830 he was a Sergeant. He married Eleanor 2 January 1830. Sergeant Roger Guerin, Ellen and daughter Dorinda born 21 January 1832 at Chatham and Ellen's 12 year old sister Maryanne Berckelman arrived Hobart, Van Diemens Land 23 April 1833 with convicts on the ship 'Isabella'. Then to Swan River arriving on the 'Jane' 9 September 1833. In 1839 Barracks were built on Roger's grant of 3½ acres so he was given 7 acres at Wonnerup which he farmed. He built 'Pigeon Grove' house in the 1840's. He also had a retail dealers license and liquor license. In 1843 he had a licence for 'The British Fusilier' at Wonnerup. He was stationed at Augusta and Vasse. When the Regiment left for Calcutta in 1840 he remained, being listed as 'at Swan River on furlough on discharge receiving no pay' till July 1845. Dorinda was married October 1849 at 'Pigeon Grove' by Registrar Captain Molloy to Henry Thompson Ker born 1824 at Greenock, Scotland. Henry and Dorinda had four children. Her father Roger died 3 June 1878 and mother Eleanor died 16 January 1878 at Busselton. Both are buried at the Old Busselton Cemetery.