In which we get to see some fabrication of small repair panels. Over to you, Barry:

With the recently replaced floor edge, together with the soon to be replaced A-post base area removed, work could start in tidying up the base of the main inner member (sill, chassis rail? You decide).

As you can see, the previous repairer had attempted to weld individual holes up. Sometimes this is fine if it's one or two isolated holes in otherwise good metal. In this case though, the whole area was replaced. Same principle was used all the way along. In the end, just one repair was retained right at the rear of the run. Not shown in detail, but that thin area near the round hole was replaced at the same time.