@AC Vienna Convention - Re: What a horrible waste of time and money
[[Vienna convention comments]]
Others disagree - http://www.connexionfrance.com/Vienna-Convention-1969-expats-rights-residence-Brexit-17867-view-article.html
Particularly of note to my situation - UK citizen residing in France - is that France opposed the Vienna convention and didn't sign it, so that's not a good start.
The money quote: "The London School of Economics’ professor of EU law, Damian Chalmers, said: “Basically, this argument of acquired rights for expatriates has nothing going for it. " "
Lots more explanation in that article, but their conclusion, to paraphrase, is "don't bet on it".