I'm confused! As I understand, 3 couples go into the final which is 17th December - 4 more shows

According to the Radio Times, Saturday's show was 9 of 13 tieing in with the above, however there are 7 couples left which makes 4 in the final?

Am i correct (maths isn't my strong point!) does this mean 2 will go one week?

Yes. If someone hasnt pulled out by the semi final stage, then there is a double elimination at the SF... like last year when Gavin and Scotttt went.

Thanks! Should be an interesting week then