I saw this on the news, from what it sounded like, the cadbury delivery ppl check the store's stock when they deliver to be sure there's no affected ones there.....but that could have just been in Hamilton where the Cadbury plant is.
Just make note of the UPCs....you should be fine!
Besides, it's not like there's anything toxic in them, it sounds like a piece of machinery just may have broke in a batch and gone un-noticed. Don't eat 'em whole and you should be good! lol