Green’s Dictionary of Slang

flatch adj.

In compounds

flatch-kennurd (adj.) [kennurd adj.; lit. ‘half-drunk’]

tipsy, mildly drunk.

1859, 1860		Hotten Dict. of Modern Sl. etc.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 23/2: Flatch kanurd ... Half-drunk.
1874		Leeds Times 28 Mar. 6/5: Somebody suggested that Cuttie was probably ‘flatch kennard’ by this time.
1909		press cutting in J. Ware Passing Eng. of the Victorian Era 43/2: When a bloke is flatch kennurd the booze pushers will give him any rot in the house, and that’s very hard lines.

flatch yenep (n.) (also flatch yennep, flatch yennop) [yennep n.]

a halfpenny.

1859		Hotten Dict. of Modern Sl. etc. 127: FLATCH YENEP, a halfpenny.
1861		(con. 1840s–50s) H. Mayhew London Labour and London Poor I 23/1: Yenep-flatch ... Three half-pence.
1873		Sl. Dict.
1933		Derby Dly Teleg. 7 Aug. 6/4: Back-slang [...] of which the costermongers of London boast [...] flatchyennep (halfpenny), nos-rap (parson), and kirb (brick).