The Disappearance of Mr. Davenheim - S2-E5
Other mistake: When Japp and the bobby arrest the pickpocketer, the dialogue says "It was only last week that we put him inside for three months" which obviously does not make sense. In the original story he did the 3 months of jail the year before, and this has to be a flub in the lines of this TV version (it is specified also that he did those in the winter, so the Sergeant can't possibly mean that he was released last week). (00:35:00)
The Disappearance of Mr. Davenheim - S2-E5
Other mistake: Lowen allows Hastings inside his Bugatti, but then leaves to join a member of his staff who beckoned him. We actually see him in front of the staffer and the person with him. Cue Japp, who has then a little comical interlude with Hastings for about 20 seconds. Cut then to Lowen who.is just now being introduced to the guy he came over to greet. Surely he has not been standing in awkward silence all that time. And even if we assume that this conversation is supposed to happen simultaneously to the Hastings and Japp show, it is half as short, meaning it would have cut into their antics when he ends it by yelling at them. (00:23:15)