Green’s Dictionary of Slang

1. a whore.

1935		A.J. Pollock Und. Speaks.
1946		St. Vincent Troubridge ‘Some Notes on Rhyming Argot’ in AS XXI:1 Feb. 46: forty-four. A whore. (Origin uncertain, but probably American.) Almost certainly American. The English is five to four, or six to four, from the betting odds against horses.
1960, 1975		Wentworth & Flexner DAS.
1966		Trimble 5000 Adult Sex Words and Phrases.
2003		B. Dark Dirty Cockney Rhy. Sl. 55: ‘How was your forty-four?’ ‘She wasn’t too bad, but I feel a bit Pat and Mick now.’.

2. a door-to-door salesman.

1960		J. Franklyn Dict. of Rhy. Sl.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.