If Warnley is Bradford, what is Dufton?
You can figure out pretty early on that the movie's setting is either Leeds or Bradford. Shooting location was Bradford, as this link makes clear...
http://www.cravenherald.co.uk/bradford__district/100_years/1958.html
However, it was made in 1958, with mostly contemporary clothes and hairstyles, and this makes for some confusion. At the time, John Braine's novel was well known. Most viewers understood that the story was set in the latter 1940s, and probably weren't bothered by the updated costume design, since filmmakers in those days were seldom faithful to the style of recent past (perhaps because 40s styles seemed so depressing in the 1950s?). Viewing it for the first time today, most people have to stop and figure out why ex-POW Joe Lampton (Harvey) is only 25 years old more than a decade after the war. Another oddity is that when Joe goes back to visit his forlorn hometown of Dufton, he seems to be transported back to the past, with a grubby little girl playing in the wartime house rubble, and his aunt and uncle living in a way that makes you think of George Orwell's description of the Wigan miners in the 30s.
The contempt with which the Warnley burghers regard Dufton is a subtler anachronism. By the late 50s, the Warnleys of the North were losing most of their old prosperity, while the Welfare State had given the Dufton inhabitants something of a leg up.
It would be nice to remake the film, setting it clearly and properly in 1946 or 7.