Technology has meanwhile moved on so that people who are at all serious about photography are now moving onto aerial shots via quad copters. So I had a third go and bought a half decent, but cheap waterproof camera on Ebay, second hand, only used once in the bath and the bloke had very decently removed most of the images on the card.
I did originally get it with ideas of mounting it on the boom and taking photos of other people as I was sailing along. If anyone is thinking of trying this, it doesn't work. Even on a long board in non planing conditions it's virtually impossible. But if the wind ever returns I'm confident I should be able to get some interesting shots with this little cam (a Fujijilm XP10, 60 quid). In the meantime here's some test shots of a seal at Hengistbury Head (ok, a dog at Hengistbury Head) and my attempts to recreate the infamous Waimea Shorebreak shots, on a slightly smaller scale.