I agree. I think the bookies have got it right this time. I personally would be very surprised if the result was not:
Brian and twins to take first and second place (EITHER order) ,Liam and Carol to take 3rd and 4th place (either order) and Ziggy and Jonty to take the last two places, again in either order.
However, apart from Brian and the twins who are so obviously going to be winners and runners-up (either way round), there is less certainty about the other places. Much might depend on what happens between now and then...