Green’s Dictionary of Slang

30 shillings, £1 10s (£1.50).

1859		Hotten Dict. of Modern Sl. etc. 127: EXIS-EWIF-GENS, six times five shillings, i.e. 30s. All monies may be reckoned in this manner, either with YENEPS or GENS.
1864, 1867, 1870		Hotten Sl. Dict. [as cit. 1859].
1873		Sl. Dict.