Why are the same locations repeated in completely separate episodes? It's a resort island, people check in and out all of the same rooms all the time. Not only that, but multiple rent-able units would have been built with the same floor plan à la Cut-and-Paste Suburb.
After Catherine is discharged from hopital, she returns Parker his book on facts, and they and the team decide to use it to have an pub quiz between them, with the Commissioner getting every answer correct, even the ones he shouldn't know. While the team think he can see the answers from where he's sitting, he denies the accusation. However, he had previously stayed by Catherine's bedside while in the hospital, so it's more likely he read the book while he was there and is just remembering the answers he had read.
While the instrumental theme tune for the show is pretty upbeat, the lyrics to the song fit much more, with lines such as 'You're wondering now what to do now you know this is the end' and 'I won't return; forever you will wait'. (It's a break-up song)
Fridge Logic
I know that the Doylist answer is likely due to work visas and the like, but is there a Watsonian answer for why there are never any American or Canadian tourists on the show?
The Caribbean is made up of dozens of small resort islands. Saint Marie is probably known to many English tourists but hasn't yet caught on in the American tourist scene.
If memory serves correctly, then one of the characters (the one who kicked off the plot by coming forward as an alibi for the person who was convicted for the murder originally) in “In The Footsteps of the Killer,” was either an American or Canadian. One episode in Series 11 had most the suspects be American, but I believe they were all British actors putting on the accent. But due to the fictional history of Saint Marie, it would make sense that most the tourists are either British/Irish or French, with a few from other countries coming to visit too.
