Continuity mistake: Time to examine the photo albums just found by JP; Jack has the open folder in front of him. He's about to flip the first page, but in the close-up that follows, he already flipped two; in the following cut he just flipped the first. (00:21:10)
Character mistake: Interrogating Delmar Brown, Jack mentions to him that "Back in '85, the band went on tour to Europe." But the tour, as established by the Commissioner, Dwayne and Florence's bank statements, happened in 1988. (00:19:40)
Character mistake: Commissioner Patterson begins the narration of the past events with a date, June 3, 1988. It's the day Jasmine died. When Dwayne a couple minutes talks about the band splitting, he mentions that there had been tension before that incident, and says that the band in the summer of 1988 had a tour planned, but Jasmine put a halt to it halfway through. It seems kinda difficult for someone who dies in early June, to put a halt halfway through a summer tour (and that fact being presented as something completely distinct from the person's death). (00:14:25 - 00:16:30)
Continuity mistake: Jack and Florence are talking to Delmar Brown at his bar. Delmar pours himself some hard liquor, puts the glass down close by, and the glass simply disappears for the rest of the scene. (00:19:20)
Continuity mistake: It's a locked room mystery, and to make it more obvious the pretty aide asks how was it possible for the killer to do it. Jack answers "There's the rub, Florence"; viewed from behind, Jack has both hands on the handkerchief, but from the front, just one. (00:04:35)
Continuity mistake: When Jack declares that the case is "Still firmly open", JP has his hand above the belt, but his hand is down past the hip in the next shot. In the rest of the scene his arm position keeps being inconsistent; he has them open to different heights and°. (00:12:10)
Continuity mistake: In his initial reconstruction of the struggle, Jack says."falls to the floor just here." JP has his hat in hand on the left side of his body. Then Jack continues "and then crawls forward", with no pause. In this new shot, JP's hat is on the right side and he in a totally different posture. (00:05:45)
Continuity mistake: Crouched by the victim, Florence points out of the most likely murder weapon. Between shots she changes position on the floor, as easily shown by the large tiles on the floor; sometimes she has both feet on the same one close to the statue, other times she does not. (00:05:15)
Plot hole: The way Jack narrates the murder does not make sense; according to him, the killer went first to grab the telephone, then back to the garden to kill the victim, then from there, he had to go, unnoticed and with his robe loose, back to the shack (which seems to be close to the entrance and the box where the phone was). Moreover, to stick the rope into the clay sculpture, especially the way we see it, not entwined into a ball but unfurled, he needed to disrupt the sculpture in a way that would have been noticeable, even if the clay was not entirely dry yet.
Revealing mistake: Jack searches for Bryn Williams. We see the page with the results. Florence suggests him then to change to William Bryn, he types it, but the next close-up shows the results page with the query unchanged from before. Still, the bottom result (the top one are still all "Bryn Williams) is the one ("William Bryn") they are looking for. (00:16:20)
Continuity mistake: At the harbour, Florence's ponytail is suddenly windblown in the shot when Jack says "I'd say that gives you a pretty good reason to want revenge." (00:37:15)
Continuity mistake: Officer J.P. Hooper holds the wad of bills for an unnaturally long amount of time, but if it was for sake of continuity, too bad; he holds it with his arm at a different angle between shots (he did not have his elbow on the desk, and all of a sudden he does). (00:37:20)
Continuity mistake: The detectives reach Cressida Friend on the beach. Jack waves around the letters with his right hand; his left hand is in his pocket in the front views, but it's on the waist in the wider shot. (00:32:00)
Continuity mistake: JP presents the key after his visit to Dread Locks; Tobi Bakare is holding the plastic bag in a different way throughout the scene (just one finger in the reverse shots) and at towards the end he lowers his hand in a shot but it's again up in the next. (00:27:10)
Plot hole: One of the guests is a journalist going undercover. The police finds him out because...they google his name, "Bryn Williams journalist" (no quotation marks), but then not finding anything (and Jack says so despite actual results being visualized, but he dismisses them at a glance) Florence has a stroke of genius and says "William Bryn then." And this time the googling pays off, with a search result page that says, literally, that he's an investigative journalist "known for going undercover to investigate", apparently being a master at that having won prizes! In all this amazing silliness, it appears quite impossible that they wouldn't know his real name, since they already identified the suspects and ran background checks, which in every episode always include checking with immigration when they entered Saint Marie. He couldn't have entered the country under a fake name.
Factual error: Jack listens to an interview with the fictitious novelist Frank O'Toole who appeared on BBC 4's Radio Island Discs. The episode is labeled "Fri 9 Nov 1989", but November the 9th in 1989 was a Thursday, not a Friday. (00:16:00)
Murder on the Day of the Dead - S7-E5
Audio problem: The address on the satnav is 35 Rue Dauphin, but Ardal O'Hanlon says 35 Rue D'Orphan (the close captions say as much too, it's not a personal interpretation). Florence correctly types Dauphin. (00:35:00)
Murder on the Day of the Dead - S7-E5
Factual error: The story is set in February 2018, but when Jack and Florence go talk to Hugh Davenport, he is reading the latest finance news.from the May 4th 2017 newspaper. (00:32:50)
Murder on the Day of the Dead - S7-E5
Continuity mistake: Hugh Davenport runs off when the two police officers walk by. Jack comments on that; in the first shot, Florence lowers her hand while the wind blows. Second shot, both hands hold the evidence bag mid-waist and there's no wind. (00:20:30)
The Healer - S7-E4
Continuity mistake: Florence proposes to dance, and Jack says no; when she replies "Whatever you say, sir" the bottle of Etensel beer in her hand shows the logo. Cut, and the actress is holding the bottle in a different way, with the back label on display instead. (00:51:20)
Answer: Most likely they had only tropical exotic drinks, he wanted an old fashioned English beer.