One thing I like in British TV shows is when they throw in a reference to another show that an actor has starred in.

Miranda Raison who played Jo in Spooks played the wife of a murdered man in a Death in Paradise episode called Missing a Body. When Ben Miller's character and another one of the members of the police team are discussing whether Miranda's character could manage to shoot her husband right between the eyes, on a beach in the pitch dark, Ben Miller says something to the effect of, "She would have to be MI5 to take that shot". How he or any of the cast kept a straight face when he said that is beyond me, although I expect the director had to yell "Cut!" until they stopped laughing.

I seem to remember that in one of the early episodes of Death in Paradise there was a similar funny aside made about Danny John-Jules's character with reference to his famous character, The Cat in the Red Dwarf series.

Ardal O'Hanlon is worth watching in the show too but I keep expecting him to break into his Father Dougal character.