Deliberate mistake: Helena asks Justine over to watch Atonement, but she instead goes on her 'date' with Alexis. When the scene cuts to Helena and Emily watching the film, it's actually The Duchess.
Continuity mistake: During the sex scene between Alex Pettyfer and April Pearson, April Pearson is not wearing a shirt. However, as Alex Pettyfer is dragged out of the car, she is suddenly wearing her shirt again.