Factual error: Almost all the people being shown skydiving have no experience doing it, but the instructor allows them to jump out of the plane unassisted after only giving a theoretic introduction into the subject. First time skydivers are always assisted in some fashion, usually through a tandem-jump or a parachute opened by a line attached to the plane.
Factual error: The judge requires £100,000 to be paid to the court in bail and Yvonne's husband later says he had to cash in bonds to get the money. In Britain, bail is not paid in advance. It is sufficient to prove that it is available if necessary and it is only required to be paid if the defendant later absconds.
Factual error: The Metropolitan Police isn't a national police force (except for close protection and anti-terrorist matters). It has no authority over other police forces. It doesn't take over criminal cases from other police forces. It hasn't even provided investigation teams on request for decades. Every force handles its own investigations. A Met chief superintendent and his team coming in, as depicted here, and taking over an Avon and Somerset investigation just wouldn't happen.
Chapter Seventy-Nine: Graduation - S5-E3
Factual error: Archie revealed that he joined the Army to avoid repeating his senior year and was shipping to Basic Combat Training the following morning. Before leaving he would need to wait for his background and medical checks to be completed (including getting his dropped murder charge reviewed for suitability), which could take weeks. Also, the Army usually requires a diploma or GED to ship to basic. There were brief periods when the Army was accepting dropouts but it was not when this episode took place.