California Doubling: Guadeloupe for the fictional Saint Marie. Saint Marie is said to have formerly been French before being traded to Britain, explaining the mixed population (and actors).
McLeaned: After Ben Miller decided to leave, he was killed off in the first episode of season 3. As is usual for the victim on this show, he didn't even survive the Cold Opening.
Playing Against Type: Ben Miller is primarily known for comedy, but here plays a more dramatic role. He has a bit of previous experience as James Lester, who he played in Primeval.
Real Life Writes the Plot: A Series 7 episode ran into trouble when the actor playing the murderer died of natural causes midway through filming. The episode was hastily rewritten so the character has already fled the island by the time Mooney manages to crack the case. The episode was dedicated to the actor's memory.
Many actors appear on the show because it gives them a chance to visit the Caribbean (series 3 guest star Tristan Gemmill described it as "winning the lottery for actors").
Joe Absolom said that he actually ended up going broke while shooting an episode because he brought along his family to enjoy a tropical get away. He says he doesn't mind because he had a great time.
Averted by Ben Miller who (despite enjoying working on the show) suffered because Poole wore wool suits despite the heat and humidity (Poole was often shot from the waist up because Miller would wear shorts and sandals to try and deal with the heat). He departed the show because he wanted to be with his family but his wife couldn't stand the tropical climate.
Also eventually Averted with Kris Marshall, whose wife didn't want to be spending half the year in the Caribbean after the two had their most recent child. When Marshall returned from filming a season, his youngest son didn't even recognize him; he quit the show the next year.