I was just trying everything the other day to try and get double shuffle to work.
1 - Danced along to DVD (slow speed) 5 times.
2 - Turned round so I wasn't facing the screen and danced along 3 times.
3 - I also do straight shuffles instead of rounded ones as suggested.
Something dawned on me...if I didn't listen to the melody closely like I usually do I could dance to it much easier...as long as I remembered to do the double shuffle at the right time. It meant I could have brain free to count steps rather than concentrating on the beat. This seemed quite counter intuitive so I put it to the test. Used the 'slow' and 'medium' music on the CD to dance to...and it...worked well it seems to work.
I shall have to try it again and see if it works now I've had time to 'forget' and see if it works without having double shuffled all evening first.