This week is possibly the 50th anniversary of the oldest known surviving picture of Pan's People on TOTP. It's either from 24th Oct 1968 or 28th Nov 1968 and it's them rehearsing for a performance of The Good, the Bad and the Ugly. Either way it's a noteworthy anniversary, shame there's no footage left of the resulting dance.
Interesting you mention that, as I realized earlier this week that the Beat Club performances are also 50 years old this month. In fact, there is quite a number of surviving Pan's performances from 1968, just nothing from TOTP.
If I only had one love yours would be the one I'd choose
The first picture is from 24th October, its on shutterstock with a couple of related images, shown below. Seems this was the 250th Episode.
The picture of Dee Dee, Flick and Ruth i thought was from around May of 68 (ie their first performance as Pans People), in the book it talks about those three dancing on the show instead of the Gojos. I've never been able to match the background to another act though.