Thought Harold Holt accidentally drowned while taking a dip in the ocean? Think again. Ray Martin wants to entertain some conspiracy theories about the sudden disappearance of our Prime Minister in 1967. One of the most far-fetched notions involves Chinese Communists and a kidnapping via submarine. Next! Then there's the 'he was murdered because he opposed Pine Gap' theory. Next! Or the suicide theory, which, while not completely nutty, has been dismissed as bunkum by people who knew him wel