The bottom end of the fuel tank breather pipe.
One of the connecting plates between the hull and chassis.
The badly corroded contact surfaces are readily seen, this is why as much of the hull structure had to be stripped down to try and reach these areas.
I removed this louvre next, not much more could be removed after this because the hull structure would collapse in on itself.
A side view of the plate being removed.
And what it looks like from underneath.