The Brits have a long history of being duped by the Russians and their own fellow travelers, going back to the Cheka in the 1920’s. Almost 100 years of incompetence and treachery.
Yes. The cardinal error of the 20 century is to consider the governments on the territory of the Russian Empire past the Bolshevik putsch of 1917 legitimate.
Today, most of the nations of the former Soviet Union have legitimate national governments. Russia still doesn’t.