Factual error: The contract Stone and his team force Carlton Wood and Harry Fielding to sign guaranteeing Fowler's widow the royalties from his invention for life is signed under duress and is therefore invalid. It is hard to believe that none of Stone's team don't know this, but it is impossible to believe that Carlton Wood wouldn't.
Plot hole: Mickey Bricks returns to England by stealing the uniform of a Commander Cardwell, an officer in the Royal Navy, and taking his place on board an aircraft carrier that is sailing from Australia to the UK, leaving that day, a voyage that would take three to four weeks. During that time, Cardwell does not report his uniform stolen, nor does he report to the aircraft carrier to take up his duties, and since there was a car waiting to take him to the ship he is obviously supposed to be there. Theft of a military uniform is taken extremely seriously and once reported it would take no time at all to establish that "Cardwell" appears to be on board his ship! On top of that, during his entire time at sea nobody on board calls upon Mickey to perform any sort of military duties (of which he would have absolutely no knowledge), he doesn't run into anyone who knows Cardwell, and nobody asks to see his orders, military identification or travel warrant.
Factual error: Ash tells the gang that corrupt politician Rhona Christie "took a marginal seat", which we know includes the youth club in Poplar, Greater London. In fact Poplar and Limehouse is an ultra safe Labour constituency. The sitting member has a majority of over 20,000. It has never been even close to marginal, and a meticulous researcher like Three Socks Morgan wouldn't make a mistake like that.
Factual error: Albert and Emma pose for phony wedding photographs in front of a green chromakey screen in order to have a new background created on computer. However, Emma is holding a garland of flowers surrounded by green foliage. You can't have anything green in the foreground when using green chromakey as it will drop out too and become part of the superimposed background.
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.
Plot hole: The only people who respond to Harry Fielding's classified ad seeking victims of the gang are three people who, it turns out, are actually working with Mickey Bricks. Considering how prolific the grifters are I rather think Fielding would be inundated with genuine people seeking revenge, but not one shows up. Not one? Simply unbelievable.
Factual error: Emma gives their mark, Judge Anthony Stone, the name and address of Albert Stroller - Faverton Open Prison. Throughout the episode we see Stroller inside the prison, and we see what it looks like from outside when he is released. It is absolutely not an open prison, which would not have cell blocks and would not be enclosed in huge brick walls. The prison they show looks more like a medium or even high security inner city prison.
Plot hole: When Albert, Mickey and Emma are trying to decide which nationality of millionaire Albert will pose as, they decide not to go with an English millionaire, since Albert at this point tries and fails to do a remotely convincing upper-class English accent. However, in many earlier episodes (such as "Gold Mine") he has no problems at all in putting on a convincing upper-class English accent.