Green’s Dictionary of Slang

sherbet (dab) n.

a taxi-cab.

2002		D. Shaw ‘Dead Beard’ at www.asstr.org 🌐 Tell him that every weekend at visiting time, do you, Dionne? At least it’s convenient for the bucket and pail here. Only one sea, one ocean and a few counties to go – call a sherbert dab, do you?
2002		Guardian G2 23 May 10: She suggested in fluent cockney that we jump in a sherbet and shoot over to her local rub-a-dub for a few cheeky ones.
2015		I. Welsh Decent Ride 183: So we’re in the fuckin sherbet [...] gaun ower the Forth Road Bridge.