Thanks as ever for all the encouragement, it helps a lot.
Another 6 months has gone by so I'm overdue an update!
I left you with a pic of a sorry looking sill end.

Time to bite the bullet and cut it out

The back end of the inner sill was sort of still there!

A new corner piece was needed to link arch, floorpan, and inner wing. Out with the hammer

And it came out OK

A couple of local patches to the inner sill and an end closing plate



But what to do with this mess?

I used one of Mark's pattern sills for repair sections and them beat the whatsit out of it to get the right profile (2mm thick - heavy going)


This bit had to be made from scratch


Oops

Back on with the repaired sill

Looks good.

A new flange for the bottom of the B pillar

And in that went too

Again - happy with the result

That's the nearside sill & floor and A & B pillars done and hopefully good for another 40 years. Onto the offside rear.