The film is based on a short story called Triple Word Score, written by the script writer Frank Cottrrel Boyce.
The title refers to the Sometimes, Always, Never Three-Button Rule. When wearing a suit with three buttons a man should sometimes button the top button, depending on the style of the suit, always button the middle button, and never button the bottom button.
Arthur gets upset during the Scrabble game because he wanted to play the word 'Anadyomene' but the rules of Scrabble would prohibit this word as it is a proper noun (a name).
The computer screen images show a board with Scrabble colours but with bonus squares in the wrong places.
Alan says that Marmite isn't available in Canada. It has been available for quite a long time.