In his witty and eminently readable memoir, Privilege and Pleasure (1986), Peter Henderson opens with a reflection that Commonwealth and Northbourne Avenues, two of our national capital’s grandest boulevards, somehow formed a permanent backdrop to the important events in his life. He drove along there in 1951 with his mother for his final interview for entry as a cadet to the Department of External Affairs. A few weeks later, following a successful interview, he was driven along Northbourne Avenue to “Gungahlin”, a former homestead just out of town which housed the budding diplomats. Four years later, he and his new…