There is a discussion and tv footage of US President JF Kennedy and his assination. This happened in late 1963. Presumably well after this story.
Dr. Blake's car is a 1930's Coventry Standard.
A medicine bottle labeled NSAIDs appears in the credits at the start of every episode of this show set in the late 1950's. Non-steroidal anti-inflammatories were not developed until the 1960's