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.
Grange Hill (1978)
1 mistake in Episode #14.7 - chronological order
Starring: Gwyneth Powell, Lee Cornes, Sally Geoghegan, Stuart Organ
Genres: Family
Mr Baxter: racism, bullying.extortion, I should think that's enough to have you slung out of this school for good six times over.