This may sound unlikely, but did you once read @Major Crimson's Culture of the Fraternal Commonwealth article (readable Wikipedia:Sandbox version here; part of his Fear Nothing But God timeline), and misremembered it as part of These Fair Shores? It's the only full Wikipedia article for an alt-Britain I know of, discounting the famous New England article from this very timeline's previous incarnation, Our Fair Country.
Huh, looks like it, thanks.