done as much research on por15 as i can find so now my plan is to grind/wire wheel on drill all the rust areas then clean with marine wash. then prep and ready (metal ready) on the rust.
non rusted areas will be wire brushed or sanded to key then marine washed then the whole underside will get silver por15 paint.
the black suspension bits may get done candy red powdercoat which my mate suggested and i kinda like the idea.

hope to crack on in next few wks.