There’s a lot to be said for gentle humour, in which the writers drift away from the set-up/punchline rhythm and explore character and setting, eliciting wry smiles rather than big laughs. Go too far in that direction, though, and you have something that is neither comedy nor drama. Bob Servant (9 February) is effectively a two-hander, built around the relationship between bombastic, bullying Bob and his quieter, put-upon sidekick, Frank. In this episode, previously shown on BBC Scotland, the pair return to the burger business, finding their old van in a garage and setting out their stall on the waterfront at Broughty Ferry, a pretty suburb of Dundee.  From the start, Bob (the great Brian Cox) lords it over his ineffectual friend, whom he calls his “Director of Sauces app