Well, that's one rear arch butchered
After lots of measuring, not enough room to move wheel in and a bit too much to cut out of the lip.
Started with heat gun and arch roller (these seem to be designed to work on newer cars with wafer thin metal) ended up bashing it with a copper mallet to fold it completely back on itself at the top
To cap it all the quarter panel has distorted a bit and needs work to fix
The joys of messing around with old cars !