Had a good look at the rear valance, it was covered in underseal & looked to have been repaired before, cleaned off the underseal & filler to reveal a brazed on patch, this was removed & I was left with this
the bottom of the valance has gone almost the entire length, had a look at a sill panel I had left over from a capri, removed the flanges, & held it up the valance to check the profile
a perfect fit ! how lucky is that, it will still need some work as the valance curves the other way between the rear wings but im confident a good repair can be done