As described in historical dictionaries

Patronymica Britannica (1860)

BANGER. A provincialism for a large person, see Halliw. Or, possibly, from one of the Bangors in Wales.

Lower, Mark A (1860) Patronymica Britannica: a dictionary of the family names of the United Kingdom. London: J.R. Smith. Public Domain.


BritishSurnames.uk is a Good Stuff website.