Spanner Nut
Heat the nut with a torch being careful not to damage the agitator shaft seal.Melt the nut if necessary and chip it off it is a soft metel.
Bendix
I have wanted one of these since I saw one on Dennis The Menace.My grandmother had one but I never saw it.This one appears to have the soaplid intact.I have three of these machines but they are sad.It is not clear to me to this day what holds the soaplid in place.