Anybody know how many dances, and what dances, the final will consist of?

All the Beeb's website says is that it's all on one night, spread over two programmes.

My best guess:

1st hour: 3 couples doing two dances each: either one unlearned and favourite previous, or two unlearned. 3rd place decided.

2nd hour: Either favourite previous dance or 2nd unlearned plus showdance by the remaining two plus of course the winner announced.