@sonikk4 - good point I noticed the same corrosion on the inner sill seat belt reinforcements. Having decided to go for the complete floor pan which comes with new tunnel and inner sill seatbelt reinforcement brackets it is one less thing to worry about but I will be applying seam sealer to the edges of all parts like these.
The new floor pan arrived and it was good to see it has everything including brake and fuel pipe clips, battery cable protector. I did a trial fit before doing anything to it that would stop me returning it. I couldn't get it in a final position because a raised bit on the boot floor panel meant the heel board couldn't clear the companion bin I had left in place but it was enough to convince me it will fit. Next job was to repair the bottom of the quarter panels as doing this after fitting the floor pan would harder. I decided to remove the remaining companion bin to allow easy fitting of the new floor.

It seemed a shame but I next punched and drilled all the holes for the plug welds, cleaned off the protective paint and applied weld through primer to the bare metal. I am not sure how much good it will do but I used the spray can I had bought to test the colour to coat the bits of the sills that will be boxed in when it is all welded up



It is amazing how long drilling a few holes and a bit of painting can take but now all ready to see how it fitted. It originally caught on the the A post reinforcing panels but was easy to use a screwdriver to ease it around them - sadly the picture is out of focus but shows the problem:-

The initial fit was amazingly good but to get the jig I had made to locate the heel board subframe mounting holes in the right place it needed to go forward few mm but the foot well was fouling on the toe board.

I remember noticing on the original floor it was a tight fit here. I took about 5mm off the toe board as marked by the masking tape in the picture to allow the floor pan to move forward. The jig now could be screwed back to the holes in the boot floor that I had made to locate it.
I couldn't get the subframe mounting bolts through the jig into the heel board captive nuts, they are very close - maybe only 1 or 2mm a side out. I think the difference will be taken up by the rubber subframe mounting bushes. The subframe has been sent for powder coating so I will wait for that to come back before doing any welding.