During the opening car chase the side window behind Doyle can be seen with raindrops or other water on it despite all other shots showing it to be dry. This is most visible at the 3:58 mark.
The gunmen are stated to be students at the London School of Economics, yet their study notes relate to a course in biological sciences. The LSE does not teach courses in natural sciences, instead focusing on social sciences, economics, and politics.
When Bodie leaps out of the boot of Copeland's Mercedes and attaches a tracking device to the blue Hillman Avenger that Copeland has transferred to, the bug immediately falls off as the car drives away, but Bodie is still able to track the car to the industrial works.
In the early part of the episode Bodie & Doyle are seen driving a dark colored Ford Cortina Estate which carries a 'T' registration dating it to 1978/1979 but it is a later 'Cortina 1980' or 'Mk 5' model, too new for the registration number it carries.
When Doyle reverses the blue horse lorry after visiting the first suspect house on his list, the camera crew can be seen reflected in the van's side window.