On the 10/3/77 show when introducing the dance to "Torn Between Two Lovers" David Jensen says something like "well Legs & Co are coming back and looking just as lovely as always". An odd thing to say when it was their only appearance that week.
They were on the previous week Mishmash so it is an odd comment and usually the Kid makes sense unlike some of his colleagues. It does make me think we might be missing something but I watched the whole show and not a glimpse of Legs before the routine in question on the copy I have
Some Dancers who gave a good time, broke all the rules, played all the fools, yeah yeah yeah they blew our minds
Like you P4pm I watched the entire show soon after finding the "Torn Between..." routine expecting to find an earlier outing for the girls but there isn't one. As the Kid was one of the more reliable of the DJ's I wonder if they had recorded another dance which, for whatever reason, did not make it into the final broadcast transmitted the following day. The more one delves into the mechanics of the productions the less fine tuned one sometimes finds them to be. For instance, watching a Pans number recently I was amused to spot a female production assistant walking behind the stage, seemingly oblivious both to the girls dancing and the camera that was following her.
Although I raised this topic LNV I'm afraid I don't have a definitive answer, having already quizzed my contact without any success but given Kid Jensen's manner it seems unlikely to have been a mistake on his part. I would be inclined to the view that another dance had been planned to be broadcast earlier in the show but was edited out prior to transmission. As to your possible scenarios I doubt 2 (unless Flick suddenly decided she didn't like what she had come up with and after the previous weeks effort I wouldn't put that past her) nor 3 (how risque would they have to go to can it) and, while 1 is more of a possibility, I'd lean towards 4. Perhaps they had thoughts of a repeat from a previous week only to find it dropping in the charts.
when kid jensen presented the itv pop show 45 ,when he sometimes introduced guests or the dancers zig zag it wasnt always a straight forward zig zag are dancing to the peppers pepperbox which they did by the way ,there was always something in his introduction to try and work out