Green’s Dictionary of Slang

the female breasts.

1873		Sl. Dict.
1882		Sydney Sl. Dict. (2 edn) 2: Dairies - A woman’s breasts, which are also called Charlies.
1900–10		Stephens & O’Brien Materials for a Dict. of Aus. Sl. [unpub. ms.] 41: CHARLIES: a woman’s breasts: variants – dibs, lemons, dairies, bubs.
1909		J. Ware Passing Eng. of the Victorian Era 71/1: Charley [...] This same word is used by the general to describe women’s breasts when well developed. It is said this term also comes down from Charles II., and refers to his many mistresses, who certainly displayed their charms as never women did before. Wilder etymologists assume the word to come from Carolian French – ‘cher lis’ – referring to the painted whiteness of the attribute in question.
1947		D. Davin For the Rest of Our Lives 345: She pulls the money out from between her Charlies and stuffs it in my hands.
1960		D. Abse In the Cage (1967) 124: Hasn’t she got a lovely pair of charlies on ’er?
1989		H. Rawson Dict. of Invective (1991) 387: Among the others in this collection [F&H]: bubbies, charlies, blubber, butter-boxes, berkeleys, diddies, globes, dugs, and ‘charms’.
1997		Roger’s Profanisaurus in Viz 87 Dec. n.p.: Charlies n. 70s Tits; breasts.
2000		Guardian Sport 19 Feb. 12: Charlies on red alert, looking like she’s got a pair of corks stuck up her jumper.