I was too young to watch Blake's 7 when it first aired but I did have a cool model Liberator but it met a melty end in the fireplace. Anyways I've finally finished watching the entire run of 52 episodes and it's been surprisingly good stuff, a bleak, adult themed, Star Trek-ish space opera that romps through scifi tropes with abandon , cheap fx & very little fashion sense.
Terry Nation's setup is pretty straight forward: Blake leads a team of criminals in a revolt against a evil empire after finding a deserted alien spaceship but it's the moral ambiguity and flawed characters that adds the depth to proceedings. With a competent cast and strong scripts it rises above it's meagre roots and is well worth your time. It's a shame Sky have decided not to give it a reboot but given the mess they made of The Prisoner maybe it's for the best. Can't find any online episodes to link to but here's the opening credits.