When Bobby is left alone on his hospital bed, he picks up a newspaper and the viewer see the opposite page headline "Red Red Roses." A quick closeup reaction shot is inserted, then back to the wider view. Now the headline reads "Ladies And Gentlemens."
When Bobby picks up and reads the newspaper in the hospital the back page changes between shots.
In the opening scenes Bobby Jones is caddying on a cliff top golf course with his friend Dr Alwyn Thomas. He is referred to as having been a lieutenant in the Royal Navy repeatedly pronouncing it as "left-tenant." However, this is how it's pronounced in the British Army, whereas the correct pronunciation for the same rank in the Royal Navy is "le-tenant." In America the same word is pronounced "loo-tenant."
The chapel hymn "O Iesu Mawr" is heard being sung in a church, and in harmony. Both these things would be unthinkable in a Welsh community.
Bobby describes himself at one point as a "used-car salesman". This Americanism is beginning to creep into English speech just a bit in the 21st century, but in the Britain of the between-the-wars period, he would definitely have called himself by the equivalent British term, "second-hand car salesman".
The Bedford Duple coach seen in the first episode is a post-WW II design, although the movie is set in 1936 (as shown in the sign for Bobby's and Knocker's car sales business in London).
Marchbolt is meant to be in Denbighshire, North Wales, and yet all Welsh accents in the show are South Wales ones.