Because this story just won’t die.
Loadshedding ends last week, inverter trip, error 8, you know the deal.
Back to my debugging protocol, pull out neutrals until it stops tripping.
Found the culprit, left it unattached. Except, everything still works.
Until lunch time, when kitchen lights stopped working.
Until dinner time, when kitchen lights started working
Until morning, when kitchen lights and lounge lights stopped working.
Fun.
Electrician came out this morning, found 200V between the disconnected neutral and earth (which I’m lead to believe is not ideal).
Told him to pull all cloth-clad wires out the roof.
He found this (inside a metal pipe of course):
Nicely frayed neutral
And a live connector with a rogue inner piece jutting out to touch whatever it likes.
Fingers (wires?) crossed that’s the last of it. Old houses…
Edit: New circuit in and… it still trips 
Remove the new circuit neutral, happy days.
Electrician coming back tomorrow to debug further