TV recently had a rare showing of the 1951 released film, 'The Clouded Yellow' starring Trevor Howard and Jean Simmons. The finale of the film was filmed on location in Liverpool on a railway track (not main line) running parallel to some docks. In one scene a small pannier type steam locomotive (No 4 ) was seen bearing the letters MD&HB. Another small loco (No 21) also appeared briefly.
Has anyone any idea of the exact location, and what did the letters on the loco stand for?