Continuity mistake: Humphrey picks up the folders of the suspects from Mooney's desk using his left hand, and in the next shot they are in his right hand. (00:31:10)
Other mistake: The police boat approaches the scenes of the crime coming in from the right, in a straight line, then in the proximity of the boat they turn around it, moving clockwise, passing in front of the bow and then to the left side. When they review the readings though, the icons show a completely different story, as if the police boat approached from behind and they boarded docking right at the stern. (00:04:40 - 00:08:00)
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)
Revealing mistake: The photo found by JP in the newspaper archive is photoshopped so badly that you can actually see the line where Julian Wadham's face has been pasted onto the sailor's head. (00:44:55)
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)
Continuity mistake: Jack tells the silly story of his cuff-collecting, one-armed uncle; in the reaction shot, Humphrey is sitting with his left arm up in a recognizable position, which changes in the next shot. (00:35:40)
Continuity mistake: Jack sits at the conference table, next to Florence. She moves the hand away from the notepad, but it's back on it at the cut. (00:34:20)
Revealing mistake: Dwayne turns the volume of the computer in DI Jack Mooney's office; when we start hear him, the volume has gone up just a few notches, but it's already just as loud in the end as it is when Dwayne finishes to set it. (00:29:10)
Continuity mistake: In the Scotland Yard office, DI Humphrey Goodman turns around and finds the teleconferencing DI Jack Mooney on screen. He announces to the team "I think I may have found him", and turns around, holding the phone closer to his chest. The movement is repeated in the next shot. (00:28:50)
Continuity mistake: A business card from CityMet Bank comes into play. Humphrey points at the whiteboard with the card, but in the next shot the card becomes a magic marker. (00:23:00)
Continuity mistake: Humphrey passes the bridge and meets by chance the distressed ginger; when he startles her, the phone instantaneously switches from right to left hand. (00:03:40)
Continuity mistake: During Dwayne's annual appraisal, Humphrey holds a bic pen that faces different directions in the reverse shots (easy to tell from the cap being on opposite sides). At the end of it he removes his hand from the desk, but it is back at the middle of the questionnaire in the next shot. (00:00:50)
Answer: Most likely they had only tropical exotic drinks, he wanted an old fashioned English beer.