Of course there's also the fact that Summerlee left children and grandchildren behind, Challenger a wife (I can't remember if he has kids or not), and I think your right about Roxton's mother probably being alive. They all have loose ends to tie up in the civilized world, even Veronica. I mean she MUST have some family back there, cousin, aunts uncles, or grandparents that she might want to find.

A return to London (or Africa, where were they when they entered the plateau?) could be interesting. I'd kinda like to see them all make it back to the civilized world for one episode (or maybe a two parter) and then somehow be sucked back to the lost world. Returning them would be no problem considering TLW writers unique ability to er "borrow" material from other shows ... hey maybe Dorthy's twister could take them back, just hope it wouldn't drop 'em off in Oz by accident! :) Anyway, we could meet the snooty Gladys (Veronica would probably punch her hee hee), the disbelieving collegues of Summerlee and Challenger ... the possibilities are endless! :)