Green’s Dictionary of Slang

norwicher n.

[ety. unknown; Partridge suggests stereotyping, as in the rhyme ‘Essex stiles, Kentish miles, Norfolk wiles, many men beguiles’]

more than one’s fair share; esp. one who drinks more than half of a shared tankard before passing it on.

[UK]Hotten Sl. Dict.
[UK]Athenaeum 15 Aug. 168: Thirsty souls! there was no restricting it. Half-a-dozen old Norwichers, after a bout of this sort, would become as hilarious and would dance as uproariously as half-a-dozen Egyptians, full of the barleywine of Memphis [F&H].