I today carried on with the re-carpeting work.
So far so good. Front side panels are done so I thought I'd replace the engine bay cover.

Four way stretch as I said before so wrinkle free.
For the side panels I actually used the old fabric as a template. The other panels I've made oversized and carefully then trimmed to size using a stanley knife. There's no room under the side glass to do this, but this method worked perfectly even if it was a little more tricky to get the material exactly lined up.

Moving on to the interior, drivers seat out, you can see how bad the carpet is after 25 years.

So main carpet ripped out (pretty easy to do) and then offside trim (just below the lever for the luggage compartment) and I find this:

Obviously I have attacked it here with my screwdriver but needless to say it was totally invisible prior to removing the panel, carpet and kickplate. It was a relatively small hole in both places but the steel was paper thin, made of rust.
Good (!) news would appear to be that you can feel up inside the actual door pillar and from what I can tell that seems very solid. Totally smooth and rust free in fact, so it seems to be restricted to the inside of the sill - there's no evidence from the outside and it's never been picked up on in an MOT or service, so I'm hoping it can be welded and patched quite effectively.
I'm expecting the other side to be the same as that certainly shows evidence of rust staining
I'd noticed this previously and it was another reason to pull out the carpets. I was expecting to have to clean and hammerite that, but now I'm not so sure.
Anyway it was booked into the local garage tomorrow to have the MOT stuff looked at, so more to add to the list.
Two steps forward and three steps back.