Des, take this with a truckload of salt, because although I gave birth, someone else raised my son. So I don't have direct parenting experience. But the first thing I thought when I read this is that it might not be the best idea to use candy as a reward for potty training. Eventually (maybe) he might expect candy every time he goes potty ... probably not a habit you want to encourage!
I dunno. Like I said, I know nothing. Just a thought. Good luck!
CB