For his service to the wounded he was awarded the Military Cross in 1916 and was mentioned in dispatches. After demobilisation in 1919 Bell returned to Edinburgh and from 1920 to 1923 he was clinical tutor in the RIE under Professor Alexis Thomson. In 1924 he was appointed assistant surgeon to the RIE. During this period he studied the development and histological appearance of the various types of testicular tumours. His conclusions, published in two important publications in 1925, came to be regarded as a significant contribution to the understanding of the development and classification of these tumours. In 1925 he was appointed to the chair of surgery at the University of Otago in Dunedin, New Zealand. Here he actively promoted the establishment of specialist surgical units and their integration into the university department of surgery. At a meeting held in Dunedin in 1927, the first steps towards the establishment of an Australasian College of Surgeons were taken and Bell was an enthusiastic supporter. He was a foundation Fellow of the Royal Australasian College of Surgeons (RACS) and played an increasingly active part in its affairs both in New Zealand and in Australia. During World War II with the depletion of academic staff on military duty, and an increase in medical student numbers, he took on much of the increased teaching commitment of his department. He retired in 1952 and was succeeded by Professor (later Sir) Michael Woodruff. In 1964 he published, with Sir Charles Hercus, a history of the Otago medical school and his autobiography "Surgeon's Saga" was published in 1968. Bell was president of the RACS between 1947 and 1949. In 1952 he became an honorary Fellow of the Royal Society of Medicine. In the 1953 Coronation Honours, he was appointed a Knight Commander of the Order of the British Empire. On 15 March 1916 Bell married Marion Welsh Berry Austin in Edinburgh. She ran a Red Cross convalescent hospital, and was awarded the Florence Nightingale Medal for this work. They were to have three daughters and one son. Bell died in Dunedin on 28 February 1970. He is commemorated by an annual RACS eponymous lecture and by the Sir Gordon Bell prize in surgery awarded by the University of Otago medical school.