Two modern London buses are visible in the opening scenes, one seen passing the Underground Station entrance at Westminster is a 21st-century model and a second modern bus is seen passing by in the background through the back of the window of a car.
On the crime pin board in the police station there is a note stating "Class 40" locomotive. They were not called this until about 1973. At the time of the robbery the were known as "English Electric Type 4's".
Leatherslade Farm has a UHF-only TV aerial, visible as the detectives look up at the farmhouse. UHF broadcasting on BBC2 did not start until 1964. BBC1 and ITV were VHF only until 1969. In 1963, a house in this location would have had a large VHF antenna.
A note at the beginning of "A Copper's tale" identifies the diesel locomotive as a Class 40. These classes were part of the TOPS numbering system which was introduced in the early-'70s. At the time, D326 would have been known as an English Electric Type 4. (D326 was later renumbered 40126 and was scrapped without ceremony during April 1984)