I first encountered the phrase "cancel two late lunches" in relation to the loss of an 43(F) FG-1 in the late eighties.( 1988 I believe, I was squadron groundcrew at the time.)
The Aircraft crashed into the North Sea, with the loss of both crew, having last been seen intercepting a four ship of Buccaneers during an Exercise (Elder Forest I seem to recall).
There was a center spread in one of the papers (Mail or Express I think) shortly after that was either about the Exercise itself or Leuchars and the RAF in general. Part of the piece touched on the crash- and used the quote above. I'm not sure if the quote was attributed to the Crew in this instance (I think it may have been) or was from another source commenting on the incident. From the other posts in the thread it would appear that the phrase had its origins some time earlier.