When Charlie and Justin attend Hector's party, they are seen taking the Central Line out into Essex, where Hector's mansion is supposedly located. They get off the train at Debden Station and are seen coming out of the main entrance and walking down the street. This scene was actually not filmed at Debden Station but at Ickenham Station, which is on the Metropolitan/Picadilly Line (as opposed to the Central) and in Middlesex (not Essex), which is on the other side of London, to the West rather than the East. Director Nick Love superimposed the word "Debden" over the "Ickenham" section of the sign, though quite why he chose to shoot the scene at Ickenham instead of Debden remains unclear. Ironically, it's unlikely that the boys would have used Debden to get to a house like Hector's anyway - if the house was supposedly in that part of Essex, it would have been more likely to have been somewhere like Chigwell.