The works ARE public domain in England. It is a matter for the ports to not permit import of such compilations as they would be in violation of US copyright law.
That is why there is a big stink over the works POST 1959 lapsing into the public domain.
A larger question is what about the works of the Beatles? I thought an American record company sold the rights to Micheal Jackson a decade or so back. Who's law applies here? BTW, If MJ renounces his American citizenship, then whose law takes precedence?
My point on American copyrighted work still stands: “No one can tell you when any song/copyrighted work becomes Public Domain because current federal law appears to allow these works to be held in perpetuity. Long after the originator has died. Don't believe me, “Happy Birthday” is NOT in the public domain.