text: * 1932  Robert Hutton     (retired 1942)
  * 1945  George Wesley Austin
  * 1958  Sir Alan Cottrell      (resigned 1965)
  * 1966  Robert Honeycombe
  * 1984  Derek Hull (retired 1991)
  * 1990 Sir Colin John Humphreys
  * 2008 Anthony Cheetham