Continuity mistake: The timing throughout this episode is bizarre. The boys leave their town in broad daylight, but by the time they get to London, it's dark. As they leave, Will's VO says they were in the club for 25 minutes, and Simon then says it's 1am, so they would have entered the club at 12:30am. Earlier, Simon said they had spent an hour looking for a parking space, so they started searching at 11:30pm. So how could they take so long to drive into London that it was broad light when they left but 11:30pm by the time they arrived? Even if they were lost in London for several hours, it would have gotten dark while they were lost, not been dark when they already arrived. This is even stranger if you consider that in the books and backstory, the boys' school is in a London suburb.
Continuity mistake: When the boys are on the Nemesis Inferno, Will sits at the front while the rest sit behind him, and this leaves the right outside seat free. However, when the roller coaster is moving, the mounted camera shows that Simon, Jay and Neil have all moved one seat to the right, meaning that Simon is now on the right outside seat instead of it being free.
Deliberate mistake: In the scene where Jay spots the "car full o' muff" and they follow the car until it turns left (just after Jay says he'd "give a left bollock for em"), when it pulls away, the shot is flipped. The number plate is reversed, all of the logos on the back of the car are backwards, and the car is actually turning right, as it heads to the right hand side of the road. The shot is just flipped to make it look like they're turning left.
Factual error: When the boys see Neil's car in his driveway, it has a registration plate. However Neil then says that it isn't completely built yet and doesn't have an engine. A car cannot have a registration plate if it hasn't had an engine installed, because the fuel type and emissions of the engine are required data for the registration process.