This was lifted straight out of the instruction book, but then interfered with slightly, because it really wasn't very interesting. The chorus, as written, only involved 1,2,5 & 6 and gave no indication as to what 3 & 4 were supposed to be doing meanwhile.
The Cardiff interpretation has a little more going on:
The middles, while all this is going on, have been ploughing an entirely separate furrow thus: moving straight from the previous figure, they set out to circle the set, both dancing out and up first, passing right shoulders at the top of the set and left shoulders at the bottom. On returning to place, they dance straight into the next figure. The trick is, of course, timing.