When Billy is confronted by his father who has just found out about his ballet lessons, Billy is wearing a beige shirt under a dark jacket. In the following shots while he runs out onto the street and vents his anger, he is wearing a dark-blue sweater.
When Billy visits Debbie at her house, he has his school bag with him (at around 29 mins), but he doesn't have it any more when he is driven home (00:35:35).
When Jackie is inside the bus leading to the mine, an egg hits his window (at around 1h 14 mins), but when the bus is viewed from outside, the window is clean (01:14:44).
The punch-bag in the dimly lit shot of the gymnasium when Mrs Wilkinson is talking to Billy is moving in one shot (at around 39 mins), then stationary in the next (00:39:21), then moving again (00:40:20).
Right after Mrs. Wilkinson slaps Billy on the face, at the locker room, we see her from behind with her hands on her face (at 00:47:33 with fingers as if praying). In the next shot, her hands are in a totally different position (at 00:47:34 with clasped hands on her face).
Jackie and Tony get off a tube train at Canary Warf and in moments they're at the Haymarket Theatre some miles away in the West End.
Billy's brother listens to music in his room (at around 42 mins) while wearing headphones but in cuts to the father and grandmother in other rooms in the house they hear the music as well. Some stereos allow the use of headphones and speakers together.
In the first scene in which Billy Elliot (Jamie Bell) tap dances, there are no taps on his boots.
When the dance teacher goes into Billy's house to confront his family about the audition at the Royal Ballet School, you can hear 'Tellytubbies', a daytime children's programme on the TV in the background. 'Tellytubbies' was first aired in 1997, some 13 years after when the film was set.
In the mobile library scene, several book spines are clearly visible, revealing titles published well after the 1984 setting of the film:
Lisa Appignanesi wrote 'Memory and Desire' in 1991, Barbara Taylor Bradford wrote 'Hold the Dream' in 1985, and 'Shirlee Busbee' wrote 'This Spanish Rose', 1986.
Police cars shown during the miners strike confrontation scenes appear to be from around 10 years prior to the '84-'85 strike.
At the end of the film, when Jackie and Tony take the tube, they are travelling on the Circle line (which would make sense, if they were travelling East from Victoria Coach Station), but appear to alight at Westminster. They are heading for Covent Garden, the location of the Royal Opera House, home of The Royal Ballet-this would be quite a walk-it would make far more sense to travel East another stop to Embankment, and then walk due North to the Garden.
When Mrs. Wilkinson drives Billy home, they go across the Transporter Bridge, which is in Middlesbrough, about 30 miles south of Durham. Assuming they both live in the same town, this is some detour.
The Young Billy has blue eyes but the adult Billy has brown ones.