In the opening car chase after the driver has dropped off the two robbers and speeds off the boot (trunk) of the Jaguar he's driving has popped open. When next seen, with the Flying Squad in pursuit, the boot is closed again.
In the final car chase, the windscreen of the villains' car is clearly covered in rain, whereas there is no sign of this (or any rain) from the outside shots.
When the robbers' blue Jaguar crashes into the oil drums and explodes in the second car chase, the car is seen to be stationary and there is no-one in the car, whereas the previous shot from inside the car shows Prince and Brass bracing themselves for the crash after Cooney has jumped clear.
The bandits force the police driver to join with them on a raid due to his ability behind the wheel, but on the raid itself he is only required to drive away relatively slowly in a way which any of the other bandits could have easily done by themselves anyway.