Unbelieveably, I searched this on The Phrase Finder, and the only near-hit I got was this:
The Phrase Finder is based in Sheffield, England so we have a special interest in
this phrase since that's where the eponymous 1990s film is set. No definitive
explanation of where the phrase originates has emerged though. The most often
repeated is the notion that it derives from the suit hire business of Sir Montague
Burton. A complete dress suit, for a wedding etc, would be the Full Monty.
Another explanation derives from a Spanish card game where the pile of cards
on the table is called a 'monte'. Yet another comes from Field Marshall
Montgomery's alleged habit of wearing his full set of medals, or even his alleged
insistence on a full English breakfast every day. Although the phrase has been in
circulation prior to the film there don't appear to be any instances of it
appearing in print before 1986. Does this now qualify as a haunting?
