Episode #1.5 - S1-E5
Continuity mistake: After Leon Hamilton is stabbed, Richard Poole gets out the whiteboard and says "this time it's personal." Yet the whiteboard has some writing on it and some pictures. If you look at it closely, it is Benjamin Lightfoot, the guy killed in the next episode when Richard is sick. So the whiteboard has everything from the next episode before it happens.
Episode #4.6 - S4-E6
Continuity mistake: When JP announces that the SIM card was sold in Isla Jonas, Dwayne in the foreground is holding his hands on the buckle of his belt the opposite way compared to the wider angle. (00:36:25)
Continuity mistake: Dwayne is staring at the boards after his superiors have gone to the church function. He says "JP..." and his younger coworker has his pen on the paper, but at the cut the pen hand is scratching his nose. (00:34:00)
Continuity mistake: When Florence "Ehh!"s and "Shh-shh!"s Dwayne, she does it with one hand, which becomes two at the next shot. (00:13:00)
Continuity mistake: Jack receives the photos of both Reverend Matthew Dawson and his wife; during the sequence, the black marker switches hand from right to left, to right again, and is pointing sometimes up, sometimes down. (00:11:20)
Continuity mistake: Back at the station, Jack picks Peter Baxter's profile off Florence's pile. Action happens in two shots, and the marker in his hand does a 180°; black cap up/black cap down. The mistake happens again later, with Catherine's picture. (00:10:50)
Continuity mistake: Fire exit scene. Everyone turns around surprised by Jack's appearance in the opposite direction. Florence turns twice, though. (00:07:20)
Continuity mistake: DI Jack Mooney arrives on the scene of the crime. He is walking with his left hand on his chest in the first shot, but viewed from the side, his arm hangs low. (00:05:25)
Continuity mistake: Catherine is chatting with the not-so-bad candidate, who offers his support. She says "I'd like that" with a bit of her scarf that goes in front of her shoulder, unlike the previous shot. (00:01:45)
In the Footsteps of a Killer - S6-E7
Continuity mistake: The forensics team consisting of JP and his DJ cousin has produced the magnified audio of the background noise featured in the taping. Everyone turns then to the whiteboard, but Florence's hand position on her mug does not match in the different shot shots (thumb on or off the rim, mug raised as she drinks, mug in front of her chest). (00:31:20)
In the Footsteps of a Killer - S6-E7
Continuity mistake: During the interview at the bar, the quantity of coconut and rum in Tony Garret's glass changes between shots multiple times. Easiest bit to spot it is towards the end when he brags that he could find a dozen witnesses in an hour; as he says that line, the liquor barely covers half of the ice cubes, but after a brief cut on Ardal O'Hanlon, the glass is full enough to cover most of them. (00:26:00)
In the Footsteps of a Killer - S6-E7
Continuity mistake: Jack recovers from Nadine Hunter's belongings a little bag containing hair. His fingers are in the middle of the bag in some shots, on the left corner of it in others. (00:15:00)
In the Footsteps of a Killer - S6-E7
Continuity mistake: Dwayne pulls up from the evidence box the gun used for the murder; he holds it at the bottom part of the handle, but he his holding it with a finger near the trigger in the next shot. (00:05:30)
Continuity mistake: When Martha says "Yes" to Humphrey, the waiter in the background has his hands free. She kisses him in the next shot, and in order to clap with the others the waiter has to put down two wine glasses he was holding. (00:49:45)
Continuity mistake: At the pub towards the end of the episode, Jack brings a glass of rum to Dwayne. He hands it to him with his left, but you can see in the shot when he begins to get seated that it's the right arm that he has extended. (00:48:10)
Continuity mistake: Up to the point when Martin West says he took the gun to 'impress the lads', Florence has her hair to the right of her face going in front of the shoulder. New shot, and there's much of it combed back, and it keeps going back and forth until it's again all in the front in Florence's next close-up. (00:26:15)
Continuity mistake: The detectives are discussing the presence of the cufflink. Humphrey asks if "He's taken his own life in remorse", and the camera cuts to the deceased. Notice an iPhone on the desk by him. A moment later, the phone rings and Humphrey has to search the victim's pockets to come up with the phone. (00:04:55)
Continuity mistake: In the intro, Dominic Green greets the client from Saint Marie. A few people are passing by the car when he opens the door, but when he closes them those people vanished in thin air. (00:01:55)
Continuity mistake: Humphrey puts on the banker's desk the printed article that establishes him as an old friend of the victim. The paper is in a different spot of the desk depending on the camera angle - you can easily tell by the upper left corner of the sheet, that either juts out from the other papers on the desk, or is properly on top of them. (00:45:10)
Continuity mistake: JP is interviewing the widow. When she is reacting to the latest questions, her hand is open in the frontals, closed in the rear views. (00:37:00)
Answer: Most likely they had only tropical exotic drinks, he wanted an old fashioned English beer.