I had £50 on Robbo when he was 8/1 after the Masters. I wouldn't place the same bet now, shame you can't get your money back.
I'm not really a betting man, I like to have the odd play, but where I see the opportunity is when you've already seen a session so have a feeling for how the match will go. That's why I only really bet in the Worlds or UK where you've got a chance to see how the match is panning out. Granted you don't get good odds, but you can end up in profit with a bit of knowledge of the game.
To show my noviceness - what do you get for an each way on the Worlds? And what does this +3.5 stuff mean?