Episode #4.4 - S4-E4
Continuity mistake: When Mr Hicks says "Move it, Stewart!" when Stewpot is climbing a vaulting box, Hicks is holding a basketball and his arm is stretched out, but when we see Hicks in the next shot, his arm is now by his side.
Continuity mistake: During the fire alarm when the staff and pupils are assembling in the playground, a boy points out judi trapped at a upstairs window to Mr Brisley by saying "sir look." There is no one behind them, the angle changes and there are now a crowd of pupils behind them.
Continuity mistake: During the memorial ceremony for Danny, Ronnie is reading a tribute but starts crying and is unable to finish it. Helen consoles Ronnie by embracing her, the angle changes to Ziggy and Robbie planting the tree and Ronnie and Helen have changed position - both are facing forwards, watching Robbie and Ziggy.
Plot hole: Becky finds the photocopies of Natasha's diary pages in Nick's locker. They all fall out onto the floor as she opens the door, she picks them all up and puts them back inside the locker. Later on at home Becky is reading the diary page about herself - where did she get it from, when she put all the copies back into Nick's locker?
Continuity mistake: While the end credits are rolling Mr McKenzie is taking a photo of Trev and Helen dancing. Behind them Gonch is dancing with Mandy. The angle changes and Gonch is now dancing with Calley.
Plot hole: Chrissy is pushing her baby Jay in her pram into the school playground. Justine and Luke call out to her from an upstairs window, then come out to meet Chrissy. They come down from an upstairs floor to the playground in five seconds, which is not enough time.
Factual error: Justine and Maria are in Justine's bedroom. Justine is showing Maria the photos on her bedroom wall of her family and school friends. There is a photo of Banksie and Zammo on the wall. These two boys left Grange Hill at the end of series 10. Justine started in series 11, so she would not have known them.
Plot hole: Gripper, Woody, and Randir are suspended from school for two weeks after their involvement in the fight. Woody and Randir appear in the next episode, but Gripper doesn't return until episode 14.
Character mistake: Gripper tells Georgie that he and Denny are bunking off their next lesson to go to the cafe, but they do actually go to their next lesson where they find Randir writing on the blackboard.
Episode #7.2 - S7-E2
Other mistake: When Claire is asking her friends for their dates of birth for her bio rhythm calculator Anita says her date of birth is 25th October 1968, to be in this school year she would have to have been born between September 1967 and August 1968.
Other mistake: Hollo goes into the hall where Perry is with Louise, Cheryl and Julie after Hollo has taken Perry's money for the bet he says "hope you win, Perry". Hollo couldn't know his name when he hadn't met Perry before or been introduced to him.
Visible crew/equipment: When Mrs McCluskey parks in the school car park camera's and crew members are reflected in the side of her car.
Episode #8.9 - S8-E9
Other mistake: When Zammo is talking to Sarah and Mandy in the street, behind them are two women standing watching the filming. (00:07:23)
