Continuity mistake: Calley and Georgina are sitting a mock exam that Mr. Robson is supervising. Later on Calley and Georgina have somehow got out of the exam and are at the unveiling of the advert in the corridor. The next scene Mr. Robson is in Mr. Hargreaves' office when Chrissie is being falsely accused of swapping the adverts over, later on Robson is back in the classroom when Calley and Georgina finish their exam.
Continuity mistake: Richard and Matthew are on reception duty, and Richard is hacking into Mr. Hargreaves' computer to see if he can find out what Hargreaves did with the money that was for the trip to Russia. The scene cuts to Mr. Robson's geography class where Justine has a message from Mrs. McCluskey to Fran. Richard and Matthew are seen in this class, but when we cut back to reception Richard and Matthew are still on reception duty.