After receiving a hint from Ms Mermaid about what might have been preventing my posts from publishing, I poked around, and managed somehow to stumble onto changing to the new editor. Now why this should suddenly let my posts go through again I have no idea, but it appears to be the case.
And the whole distressing affair had the beneficial side effect that I found my Post List, which apparently includes what was saved of all those drafts that I thought were lost for all eternity. I have uploaded the ones I've found, and may find one or two more. They are not all complete, alas, but at least people can see that I was being truthful.