Green’s Dictionary of Slang

lavender cove n.

a pawnbroker.

1859		Matsell Vocabulum.
1882		Dly Dispatch (Richmond, VA) 1 Nov. 3/3: A ‘lavender cove’ is a pawnbroker.
1889–90		Barrère & Leland Dict. of Sl., Jargon and Cant.
1895		C. Crowe Aus. Sl. Dict. 44: Lavender Cove, a pawnbroker.
1904		Sun (NY) 10 July 29/4: Here is a genuine letter written in thieves’ slang, recently found by the English police [...] I know a lavender cove and a swag chovey bloke that will toke [sic] some of the white jacks.