All the inside and underside is staying black.
Irrespective of what it may have looked like originally all of the inside is covered in carpet or vinyl so it doesn’t matter. I’m only going up to the waistline, the dash top and roof underside are staying untouched factory, which is green in places.
Having done a bit more digging everything visible from the road underneath is black, so that’s staying as per the pics above.
Arches/engine bay/luggage bay are originally poorly applied satin black over a thin coat of green. So solid black it is

I may give it a coat of statin to matt it off as the epoxy is shiny as applied.
It’s absolutely a usable car, not a show car. Even if I had the time/money/motivation for a green underside/bays I’m not sure I would.
Luckily for me the cheaper/faster/lazier route is black
