The Road Less Travelled - S5-E6
Character mistake: The plan hatched by Carlton Wood and Harry Fielding makes no sense at all. They recruit three people who they think were victims of Micky Bricks' crew, asking them each to deposit a cheque for £1,000,000 into an account that their accomplice Alfie will show to Albert Stroller to "prove" his wealth. They are on a hiding to nothing. A bank statement will always show a ledger balance - all funds including uncleared cheques - and an available balance, the amount of money in the account that can be withdrawn at any one time. Alfie's account will show an available balance of nil and will convince nobody of anything. A city wideboy like Wood would know this and would ask for the deposits to be made by account transfer or even in cash, or he could even cut out of the middle men and prepare a fake bank statement. A ruthless businessman like him would have no trouble at all arranging a simple thing like that. The way he does things is uncharacteristically clumsy and includes nothing but loose ends.
Getting Even - S4-E3
Character mistake: Albert tells Ash that during his service in the UK with the U.S. Air Force he was required to join a squad flying back to the United States in a "B29 Fortress." The B29 Superfortress was not used in the European theatre during World War 2 - it was used exclusively in the war against Japan in the Pacific. The B17 Flying Fortress was a different aircraft. Anybody in the US Air Force at the time would know the difference, and it is not a mistake a veteran would make.
Character mistake: Ash Morgan tells the grifters that "Anxious" has a basement flat in Camden, and he sends Sean there to get phoney identity papers. It is quite clear that the flat is on the ground floor, not in a basement. The front door opens onto the street.
As One Flew Out of the Cuckoo's Nest, One Flew In - S4-E1
Character mistake: Near the end of the episode Danny refers to the money they have stolen, saying "Stacie is sitting next to half a million big ones." Anyone familiar with grifter slang knows a "big one" is a thousand dollars (or pounds, etc.) - certainly Danny Blue would know that. He just said that they have half a billion dollars in their hands. Not a mistake Danny Blue would make.
Character mistake: While investigating the "robbery" at the art gallery, DS Rivet enters the sterile crime scene without wearing gloves. He not only picks up a vital piece of evidence - a discarded receipt - with bare hands, he allows the salesperson in the shop it came from to handle it, too. Not only has he hopelessly contaminated the crime scene, he has made an important physical artifact useless as evidence.
Character mistake: The amount of money the team allegedly scammed the first mark for keeps changing throughout. In the first scene, it appears to be £25K (the mark gives them this as a bribe). However, in the next scene when the team divide the money up, it is stated to be £105K. However then, in the penultimate scene, when the mark thinks Mickey has given him "60-70K" (Ash's words) from their new horse racing con, he states that he has made a 50 grand profit: thus suggesting again he was scammed out of 25k.
Character mistake: When Mickey and Emma are trying to get access to the university labs, they claim they are working for Ofsted, and are investigating exam manipulation allegations. In fact, Ofsted have never been responsible for supervising/investigating universities - they only cover places of education up to the age of 18. Completely different organisations supervise universities.