[The Philpott]

....It's actually come up better than some do, i wouldn't be too gutted about it.
As i suspected, it appears to be suffering dezincification, which in most cases runs so deep that abrasion can't remove it. Cu and Zn separate and the Cu left on the surface is crystalline in structure and quite fragile. Often accelerated by electrolyte leakage, salt exposure or being buried (i used to go treasure hunting and observed this on things like victorian toasting forks)

There must be companies who knock up replica chassis number or body number plates for classic cars..

Dave