[1] In August 1974 he represented Ireland at the World Amateur Boxing Championships in Havana, Cuba, losing in the first round to eventual bronze medalist Constantin Gruiescu.

[1][3] Larmour represented Northern Ireland at the 1974 British Commonwealth Games in Christchurch, beating Chandra Narayanan of India in the flyweight final to take the gold medal.

[1] With many African countries boycotting the games, Larmour got byes in the first two rounds, losing in the quarter final to eventual gold medalist Leo Randolph of the USA.

[3] After the Montreal Olympics, Larmour made the decision to turn professional, making his pro debut in July 1977 with a first-round knockout of Jimmy Bott.

[4] In October 1978 he successfully challenged for Neil McLaughlin's BBBofC Northern Ireland Area bantamweight title, beating the defending champion on points.