This is set in 1935, however the 'Bert Williams All Star Football Book', seen briefly about Gordon's person, was not printed until 1951. Bert, the Wolverhampton Wanderers and England goalkeeper, didn't play league football until 1937.
The goalposts at the Sewerage Works ground of Barnstoneworth United are metal cylindrical frames of a type that were not widely used in Britain until the 1970s. Typically, the posts at the time would have been wooden square frames, typically made from Douglas Fir.