Mr Muirhead, we are told, "attended Lockleys Primary School". He's an executive director of the global advertising firm M&C Saatchi, whose website profile of him tells us that he worked in London from 1971 and implies that he's been living in New York since 1994, so perhaps he only lived in SA as a child (like Tony Blair).
There's a photo of Mr M on the Saatchi website, and a 1999 portrait of him in the British National Portrait Gallery's collection which shows him as a Dennis Waterman lookalike gingerly bestriding a pinball machine.
The Agent-General's position is not a diplomatic one (if it was Mr Downer or Mr Howard would have to appoint him). It is essentially a marketing one. As Mr Rann says :
Mr M himself is quoted as saying
I wonder whether Mr M will come up with a single word which SA can own and, if so, what that word might be.