Green’s Dictionary of Slang

Errol Flynn n.

the chin.

1978		Maledicta II:1+2 (Summer/Winter) 119: Errol Flynn = ‘chin’, Vera Lynn = ‘gin’, and murderer Dr. Crippen = ‘dripping’, as in cookery rather than in the clap, have stayed in the language though they have passed out of the news.
1979		R. Barker Fletcher’s Book of Rhy. Sl. 6: Errol / Errol Flynn / Chin.
1981		P. Wright Cockney Dialect and Sl. 105: Erroll Flynn ‘chin’.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.