I've never even heard of sandboarding before, but it sounds like fun, and a lot warmer than snowboarding. I would have thought it would be more difficult to find the room to do it though, what with all the people on the beach.
Aah Bryony, it's not done 'on the beach' per se. You go to where there're high, steep Sandhills, like Stradbroke Island, & 'surf' down them.
Only problem is you've got to trudge back to the top again! Lol!