The "Boat Race" photo is attributed to 1981 within the REX Photo Agency files. Unfortunately there's no explanation for the reasons behind the photoshoot. Maybe the girls' careers were gradually "sinking" on TOTP!!!
Here's an interesting one for fans of Lulu found on the "Alamy" Agency website today. It is explained thus:-
"A new Disco danced called "Disco Smooch" has been created to be danced to pop group "Child's" new recording "It's only make believe". Lulu of "Legs & Co" demonstrates to pop Group "Child". L/R: Mike, Tim, Keith and Graham, the new "Disco Smooch". July 1978"