Why the fully armored battlecruiser remained a British idea

Which non-British designs qualify as fully armored battlecruisers?

Almost none; the category reflected distinctive British global-deployment requirements, while other navies generally built fast battleships.

The G3 design and HMS Vanguard are offered as British examples of the fully armored battlecruiser idea. Other navies generally arrived at similar fighting qualities through the fast-battleship category instead. Britain retained a separate conceptual niche because imperial cruises and distant deployments demanded additional living and operating space. After World War II, aircraft carriers increasingly absorbed the global-presence role that had sustained the distinction.