Humphrey's head really isn't very successful in general! I think the plague girl may have appeared briefly in series one, but I couldn't be sure.

That's what I love about the series - all the little things from each of the ghosts, and the way they still have their opinions, despite not being heard. Robin is my favourite, so it was lovely seeing him have a major role. When I say favourite, that's not to say that the others don't equally have their own place.