[9] A part-time officer in the 59th (4th West Lancashire) Medium Brigade, Royal Artillery of the Territorial Army (TA) during the 1920s and 1930s, Dimoline had risen to be second-in-command of the regiment by 1939.
He was then charged with raising and commanding a duplicate regiment as the TA rapidly expanded just before the outbreak of the Second World War.
He commanded the 68th (4th West Lancashire) Medium Regiment at the Battle of Keren in East Africa and then in the Western Desert.
In March 1942 he was promoted to Commander, Royal Artillery (CRA) in 4th Indian Infantry Division,[10] serving with it in North Africa, Tunisia and Italy; he was also acting commander of the 4th Indian Division during the Second Battle of Monte Cassino.
Dimoline served as Honorary superintendent Auxiliary Police, Federation of Malaya,[5] during the Malayan Emergency.