"retiring age", except in the expression "minimum retiring age", means seventy years of age in the case of a person holding the Office of Comptroller and Auditor General, sixty-seven years of age in the case of a person who is a Commissioner of the Irish Land Commission appointed pursuant to section 4 of the Land Law (Commission) Act, 1923 (No. 27 of 1923), and sixth-five years of age in the case of other persons;