Green’s Dictionary of Slang

net-yeneps n.

ten pence.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 23/1: Net-yenep ... Tenpence.
1873		Sl. Dict.
1935		R.T. Hopkins Life and Death at the Old Bailey 65: Costermongers invariably use the following terms in discussing money transactions [...] Net-yenep – Tenpence.