What got you "convinced that Metternich would have been a Brexiteer"? The fact that Metternich didn't like empires seems hardly enough for such an important statement. What would Metternich have had to say about all the other negative consequences, like isolating a country, putting it at the mercy of another empire (USA), just to name a few? Brexit seems to be more like a revolution of the working class, something Metternich would have deeply distrusted.

> "Siemann does not believe he ran a police state, not least because Austrian cities, towns, and villages had no police forces."

In Austria the name of Metternich has been and still is synonymous to the police and surveillance state. (Comments on recent ambitions aimed at more intrusive policing and/or surveillance commonly run by the tag line "Metternich2.0".)