Question:

In what appears to be a 4 couple dance, (with everyone dancing the first 24 bars), how and when does the dancing couple progress to the bottom?

Answer:

At the end of bar 32 the original 1st couple should finish in 2nd place. All four couples then dance bars 1-24, finishing with the original 1st couple in 2nd place facing down and the original 3rd couple facing up, ready to dance the last 8 bars. 1st couple finish by dancing under an arch made by the third couple and dancing down to 4th place, while the 3rd couple dance up to 2nd place, and the 4th couple step up.

It is recognised that this would make it a very tiring dance, and it would not be unreasonable for the dancing couple to dance down to 4th place under an arch made by the 2nd couple (or even all 3 couples) at the end of the first repetition.