Continuity mistake: When the squad are following Don on the motorbike in their white Ford Cortina they turn outside a shop called "Chelsea Typewriters". In the shots taken inside the car there is a white Riley parked between the red Fiat and silver Datsun, but in exterior shots there is a space where the Riley is parked.
Continuity mistake: When the Jaguar is driving across the wasteland some accident damage to the front offside wing and rear door appears that wasn't in previous shots.
Revealing mistake: When the Jaguar crosses the pavement to go down the alley you can see a plank of wood in the gutter so the Jaguar can mount the kerb more easily.
Answer: Scripted.