Here is a picture of the wheel arch - the area in question. As you can see it is all rusty and I cannot see whether the wheel arch continues in one piece with the rear bottom. Or whether the rear bottom is made out of another panel and then welded to the wheel arch (where there is the reinforcement plate). Area is marked on the photo. Would you have a picture of this area from your GPAs, what do you know about this? My GPA is the early type (GPA430).
All help and advice appreciated.

Some restoration pictures
http://s25.photobucket.com/albums/c83/gpa430/
Thanks