Green’s Dictionary of Slang

1. the rent.

1927		Hartlepool Northern Dly Mail 28 Jan. 5/5: I have also learned [...] that ‘The Duke of Kent’ means rent [...] ‘Charley Prescott’ waistcoat, ‘Woolwich Piers’ ears [...] that a policeman is known as a ‘grass’ — short for grasshopper which rhymes with ‘copper’.
1932		‘P.P.’ Rhy. Sl. in DSUE (1984).
1935		Thieves Slang ms list from District Police Training Centre, Ryton-on-Dunsmore, Warwicks 4: Duke of Kent: Rent.
1938		L. Ortzen Down Donkey Row 11: Duke of Kent – Rent.
1962		R. Cook Crust on its Uppers 29: I no longer had a lease down there, down to not paying the duke.
1968		J. Alard He Who Shoots Last 124: ‘[D]a next thing ya knows, dey’ll be puttin’ up da Dook of Kent’.
1977		D. Powis Signs of Crime 182: Duke of Kent Rent.
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 7: The Duke of Kent was needed and she needed to pull at least a half a country cousin of little brown jugs.
2002		D. Shaw ‘Dead Beard’ at www.asstr.org 🌐 ‘Who’s paying your duke of kent in this manor?’ I ask Dionne.

2. (Aus., also dukers) a cent.

1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xxxiv 4/4: dukers: Cents. A very new expression creping [sic] in with the advent of dollars and cents. Shortened from the rhyming Duke of Kents.
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 24: Duke of Kent [...] cent. [Ibid.] 25: Dukers Cents.

3. a homosexual [= bent n.].

1978		Maledicta II:1+2 (Summer/Winter) 116: The concentration in that article on proper names produced [...] and people’s titles (Duke of Kent = ‘bent’ which is the equivalent of the American twisted sexually but not as queer as kinky).
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.

4. (Aus.) a tent.

1983

R. Aven-Bray Ridgey-Didge Oz Jack Lang 24: Duke of Kent [...] tent.