Mork and Mindy was great, particulary as it featured Robin Williams - One of the few American comidians that I find funny. I was mainly looking for UK TV shows but thanks for the reminder anyway. A more recent US show that was brilliant too was "Resident Alien". I can't remember too much about "Third Rock" but I think that was US based too?

Clangers - definitely and obviously British but I am not sure it is classed as a comedy. Although I just spotted that Michael Palin narated the third series in 2015 :-) Must look it up.