Failing that, does anywhere sell an accurate mild steel version? as original.
I've never seen a stock stainless steel exhaust system.
The steel ones are readily available and reports are that they are a fine exhaust but here in the USA they are all imported from Denmark apparently.
As near as I can figure one manufacturer has the world market sewn up! Afterall what kind of demand it there for an exhaust system that fits a car made in the 50's ??
Maybe over in the "old" country, you have some OEM stuff floating around??
With enough money, you can get anything you desire custom made.