When Luther and Ripley are driving in Luther's Volvo, there is a roof shot as the car moves through London. The roof of the car is smooth and uninterrupted, no sunroof. The next shots are from within the Volvo: the shots of Luther clearly show a glass sun roof.
The final scene has Luther and Jenny getting a 99 ice-cream. The first part of the scene has a soft-serve ice-cream (white). The final part of the scene switches to a yellow frozen vanilla scoop ice-cream.
At the end when John and Jen are eating the ice cream, there is a cookie wafer stick in the ice cream. When the camera view changes the cookie wafer in John's cone disappears.