Ohh, that Lost in Space robot looks a lot nicer under your paint than I'd expected from BCB's website, Overlord.
It's also worth mining the Black Tree Doctor Who range for 1960s/1970s civilians, as well as the superhero ranges - Herolix, 4-Color Superfigs (from Old Glory in the US) and Fighting 15's "Mutants and Madmen".
As well as KKBB, lots of the character minis in Artizan's "Thrilling Tales" range are useable.
For British soldiers, the Gripping Beast Mo-Fo Falklands war range is your best bet. You could also try the Mongrel and Britannia Congo ranges for mercenaries.
EDIT I forgot to mention Hasslefree. Most of their minis are probably too modern for 7TV, but they can, at least, provide you with a full set of Meddling Kids and their dog.
Oh, and if Khurusan get their 28mm range back up, there are some very useful 1970s personalities there too.