When Does "The Full Monty" (1997) Take Place?
"The Full Monty" is a comedy film written by Simon Beaufoy that released August 13th, 1997. So when is "The Full Monty" set?
It takes place in the year:
We know this because partway through the movie David Horsfall gets a job at an ASDA supermarket and ASDA was founded on February 19th, 1949 AD. So it must be after February of 1949 AD.

1997 AD
We know this because partway through the movie David Horsfall gets a job at an ASDA supermarket and ASDA was founded on February 19th, 1949 AD. So it must be after February of 1949 AD.
Also, the guys all rent the movie "Flashdance" (1983) on videotape to learn some dance moves and the film released on VHS in England on March 5th, 1984 AD. So it must be after March of 1984 AD.
Furthermore, at the end of the 1972 AD found-footage prologue there is a white-on-black relative time setting title card reading "25 years later". The opening's Sheffield city promotional material is taken from a short film titled "SHEFFIELD... City on the move" made in 1972 AD in the real world. It's most logical to place this found-footage short film when a viewer within the fictional universe (diegesis) of the film could first see it, in 1972 AD.
1972 + 25 = 1997.
More specifically, the posters advertising the "WOMEN ONLY" event clearly say, "SAT. MAY 25TH". So it must be May of 1997 AD at the end.