This is a song about neo classical buildings and in particular the Mansard Roof, which was popularized by the French architect Francois Mansart (1598-1666). The Mansard Roof has two slopes on each of the four sides and they were considered especially practical because they allowed usable living quarters to be placed in the attic. Mansart used these double-sloped roofs so extensively that they were coined 'Mansard' after his name.
The song also references the war in the South Atlantic between Britain and Argentina in 1982.
In The Beatles "When I'm 64," Paul McCartney asks a woman if she'll still be there for him when he's 64. In 2006, he got his answer when shortly before his 64th birthday, he and Heather Mills separated.
New Order took the title for "Blue Monday" from an illustration, which read "Goodbye Blue Monday," in the Kurt Vonnegut book Breakfast Of Champions. The image referred to the invention of the washing machine improving housewives' lives.