nice work Spanner...
Rod,
As JB said most of them rust out here.
time to get under and get dirty I'm afraid.
The job is a little bit involved,but is fairly straight forward.
rusted out at the subframe attachment point.
cut out the rust and re-fab the inner sill.. the bolt was used for alignment. A threaded rod to the inner mount was also used to establish the correct position.. lots of measuring here.
If you are lucky the outer hole will be there to help get the proper geometry.. if not.. repair this section first to be used as a reference point later.
Folded steel channel crossmember repair. I prefer to make my own than to try make the repro ones fit... it's faster and more accurate.
Finished job including the floor repair as viewed fro below.
hope this helps
Ed