Early in the show Tim announces Mrs. Brown stole his wristwatch. A few minutes later Tim and Martin go to Mrs. Brown's abode Tim is wearing a watch. Within minutes he claims to have found the stolen timepiece.
When Martin is home after being released by the police hoping Martin will lead them to the diamond, Martin is wearing a light blue flat cap. When Martin uses a machine to locate the whereabouts of the diamond, he's not wearing the cap. Next scene he's wearing the cap again.