I managed to get it off the trailer today and back onto the spit, as I did want a look underneath.
I found 2 spots at the top of the rear wheel arches where the paint and rust was removed but no ecoat!
It looks like a large bubble of air was trapped in the arches - at least if they are airtight they are water proof.
The underside is good too, little areas of evidence of light rust removal, but most really good, again more pictures
FF transmission tunnel
Driver's side floorpan
Rear end of transmission tunnel
Rear passengerside floorpan
FF mods in more detail