When I did the research into Bedlington Mechanics FC and then widen it to all the local pit village teams in Bedlingtonshire, I focused on after WW2, from 1945-1965. I have some detail regards various Choppington teams that played in either the Miners Welfare League, the Ashington Welfare League or there was one (Choppington High Pit FC)who played in the Coquetdale League. However, on looking at these teams after WW2 there is no mention of a Choppington United FC.
You might do better searching old copies of the Morpeth Herald, as well as the Blyth News and/or Ashington Post.
I did try and find some details of Bedlington United FC from the very early 1900's - 1930, but really struggled as the newspapers only carried reports etc. direct from the clubs. If no-one bothered to report on the teams and results then there wasn't anything in the papers.