One of the things that made Being Human (UK version), interesting to me was that, in season 1 at least - which was all I watched, there was no “injected mythology”. And by that I mean, there wasn’t some guide or mystic texts or Handbook for the Recently Deceased to tell the characters what they were supposed to do. Instead, they had to rely upon whatever they’d gleaned from popular culture about their situations. Sometimes their information was misleading! It was refreshing! Much of my interest in the show came from seeing how they would work through their situations, because the show only fed you small bits of the mythology it was using, so you couldn’t work out ahead of time too much about what was going on.
I mean, the vampires know things and have their own culture, but even they aren’t completely infallable. They exist more as long-lived anarchists than as well-informed observers of history. And their information was always suspect and full of bias.
By contrast, Buffy was completely reliant upon an injected mythology. This took the form of the Watchers’ Council and various magical and mythological texts that were assumed to exist and be truthful in the show’s universe. Of course, with a show that relied on new and challenging monsters showing up every episode, rather than classic standbys, this injected mythology was necessary to be able to solve each new dilemma quickly. Difficult challenges were reserved for each season’s “Big Bad”, where the texts generally failed the gang and provided an over-reaching story arc for the entire season.
I quit watching Being Human because I liked the characters a lot less by the end of the first season than I did at the beginning, and also because it was depressing as fuck, so I don’t know if they changed how the characters gained information about their situations. Since season 2 deals with academians chasing after Mitchell and George, so I would assume they would also act as a source of injected mythology. It seems like it’d be hard to keep the show rolling without some outside source of new information, anyway.