Top of the Pops, 14 January 1971:
Pan’s People dance to We’ve Only Just Begun by The Carpenters
From the old blog, Saturday, 23 October 2010:
We haven’t seen any Pan’s People here for ages: to remedy that, here they are dancing to We’ve Only Just Begun by the Carpenters, from a recent TOTP2 repeat.
Going by the maxi-length frocks, the patterns and colours, and the fact the Andi and Flick are still in the group, I’d guess this was from 1970. Oh wait, look: it says “Jan 1971” right there on the clip. Duh.