Some pics of rear arch rust - I'm planning to weld some new plates in (on 3 sides) and then finish off with fibreglass where the plates meet the outer body so as not to damage the paint work and panels.
Once the plates are welded in, what do folks recommend to finish off? eg Hammerite, underseal or no underseal??
(I'm undecided on underseal, it has its benefits but Ive been scraping a lot of it off)