pd: That is a fabulous set. According to my reference..."The Hornby Companion Series, The Hornby 0'gauge System" by Chris and Julia Graebe, New Cavendish Books, London 1985. The LMS 101 Tank Engine was one first locomotives to return after the war and was one of the more readily available engines postwar (wartime shortages continued to hinder production of the Hornby line) and was available from 1947 -1954, There is listed a "101 Tank Engine Passenger Set" but the book does not list the contents. However the LMS / LNER No 1 passenger coaches that you have shown in your picture are likely candidates. These coaches were available post war from Nov 47 to Mar 59 mostly in the color scheme you pictured although there were some other liveries. The postwar versions are known by their light grey roofs. So my reference would confirm your feeling that your set was from the 1950's although it could be as early as 1947. GREAT FIND!!!
Best wishes
Don
