Yesterday I removed the rear leaf springs. They'd obviously been firmly in place for the last fifty years and I was beginning to think I'd have to grind the bolts off when I suddenly remembered that I'd been given a tank of Rost Off by a friendly mechanic, so splashed some on and went for a cuppa, to give it time to work.
Quite a bit of walloping with a hammer was still needed to crack the rust, but all nuts very soon released and, once under way, the spanner could be yanked around without doing me an injury.
No nuts were damaged and the threads aren't that bad.
Good stuff! I wish I'd known about it when I started dismantling the van.