Green’s Dictionary of Slang

goose’s neck n.²

a cheque.

1969		S.T. Kendall Up the Frog 11: Will yer sausage and mash a goose’s neck for me?
1971		J. Jones Rhy. Cockney Sl.
1983		R. Aven-Bray Ridgey-Didge Oz Jack Lang 29: Goose’s Neck Cheque.
1992		R. Puxley Cockney Rabbit.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl.