Continuity mistake: Humphrey found the cigar butt inside Newton's ship. He goes with his ever-smiling sidekick to interrogate him, finding him in asleep with a flask of booze between his hands. Cut, and Roger Griffiths' hands are on top of the flask instead than the bottom. (00:20:10)
Continuity mistake: Florence finds the divorce papers and calls Humphrey's attentions on them saying "Sir..." There is a paper sheet leaning by a corner on the laptop's right side. When the tabletop is again in frame (when Humphrey puts the coin back in the safe) the papers are arranged differently. (00:18:30)
Continuity mistake: The police are inside Tosh's boat, and Naomi Walker pokes downstairs to tell them that all his stuff is there and to help themselves. She has both hands on the manhole, which becomes just the right hand at the first cut. (00:17:25)
Continuity mistake: Humphrey grabs the ashtray in the boat; the cigar butts are placed differently on it between shots. (00:17:25)
Continuity mistake: Sam Walker is holding back his dad Tosh, pulling him apart from the rival Newton Farrell. When Tosh snarls "Get away from my boat", his son has his left hand on his shoulder, but it's behind his back in the intermediate reverse shot. (00:01:25)
Continuity mistake: Classic mistake of the series (happens at least in a couple episodes per seasons); the Detective Inspector writes down names on the whiteboard, but they are written in different penmanship in close-up compared to the wider angles. In this particular case, the detail that is most telling is how Humphrey puts a little underline on some of the names, which is at very obviously different distance for the victim and the pastry chef. (00:14:00)
Continuity mistake: The DS, DI and Officer Myers are looking at JP when Dwayne says that there's "trouble in paradise." The bottles of beer turn in their hands in between shots. (00:50:20)
Continuity mistake: When Dwayne informs his bosses that they used to call him "The Shaquille O'Neal of Saint Marie", he is suddenly leaning again against the bar post, he was not before the cut. (00:50:05)
Continuity mistake: It's time for a motive for Kim Sweeney, and the inspector and DS go to interview her. She is in her bed, surrounded by used paper tissues, which change position between shots. (00:33:45)
Continuity mistake: During the conversation with Anouk Laban, Humphrey Goodman gets all defensive saying that "we're not all like that", placing his hand on his hip. Before and after this attempt at humour, Kris Marshall has his arm on the bar counter. (00:21:50)
Continuity mistake: The victim's fiancée prepares a green smoothie and answers the questions of the police about the private investigator's findings. When she points the picture on the counter, notice how in close-up there are no photos directly by DS Florence Cassell's arm, and in the other shots there are. The whole position of the pictures seems to vary at each cut. (00:20:50)
Continuity mistake: Goodman and Cassell are interviewing the pasty white brother of the victim at his hut. During the scene, the folder Humphrey holds close to his body is positioned differently (horizontal/vertical) as the two main camera angles alternate in the dialogue. When Gary puts on a shirt, the folder even switches hands, blatantly. (00:18:10)
Continuity mistake: Florence drives into the pothole by Goodman's instructions; when he goes "Whaa!" and throws the papers in the air, the actress' hands turn around on the wheel, with the right hand at 2 o' clock - but it's nowhere to be seen in the next shot, and the left is almost at the zenith, when the wheel was turning the opposite direction. (00:17:40)
Continuity mistake: When Florence calls Humphrey's attention announcing that the brother of the victim has a criminal record, she's holding the pen with the cap towards herself. Cut, and the pen is pointed in the opposite direction. (00:16:30)
Continuity mistake: DI Goodman holds the recently sharpened knife and goes through a few smug ways to tell Dwayne the chef was left-handed. The knife faces a different direction depending on the shot's angle - towards Dwayne in Danny John-Jules' close-up, upwards when he says 'left-handed'. (00:07:30)
Continuity mistake: Commissioner Selwyn Patterson puts down at the end of the episode a deck of cards and the glass with his drink. He then helps Aunt Mary up, and with the table again in view, both the deck and the glass shifted to the right by a couple of tableboards. (00:44:50)
Continuity mistake: When at the end of the denouement Neil Jenkins and Freddie Hamilton are face to face, the tears that were running all the way down the face of the actor have been wiped clean, leaving just a bit below the eye. (00:45:10)
Continuity mistake: When Humphrey opens the bag, various items fall on the table including a small trophy cup, which lands perfectly vertical on its base. In the subsequent close-up of the messy table, the cup is lying down, and all the various items (look at the conch) are just scattered around differently than before. (00:45:00)
Continuity mistake: Ella, when asked, says that she does not know about the money, and leans back with her left hand on the lounger - but she has her arms in her lap in the next shot. (00:32:20)
Continuity mistake: Neil Jenkins starts spilling the beans about being previously acquainted with Robert Daws' character. Right before the flashback when he meets him at the hotel, he is putting the towel around his wife's shoulders, at the edge of the frame. Several seconds later, after finishing the story, his wife is sitting on the lounger and he puts the towel around her shoulders again, this time with better framing. (00:32:30)
Answer: There's probably no particular reason. Sets and props on long-running TV shows often change as needed and for various reasons throughout a series run.
raywest ★