The school scenes were shot in St Dunstan's College in South East London.
The dancers only had 3 rehearsals before the shoot day to get the dance spell choreography complete.
During the rehearsal process they broke 4 out of 5 wands and all the broomsticks, which then needed to be replaced in time for the shoot.
When shooting the King's Cross scenes, the production team did not have the right license and had to cheat the shot by shooting on a brick wall outside another station in East London.