Knowing a locale can sometimes spoil things.

Early episodes of The Bill was filmed near the office where I was then working in the East End.

To film a conversation in between driver and passenger in a car they shoot all of one side then all of the other and edit them together. The driver was driving along The Highway towards The City and the passenger was travelling up Cable Street towards Limehouse.

Never watch Morse too closely if you know Oxford. He regularly drove off in the opposite direction to wherever he was supposed to be going.