In the 1940s and right up
In the 1940s and right up until 1950 the Socialist Standard carried on the front page “Registered for transmission to Canada and Newfoundland”. Maybe we still are, but since the “printed paper” rate for postage within the UK was abolished a few years ago now, there is no advantage in any newspaper being registered. And the Post Office no longer delivers mail. Still, the old bye-law might still be in operation. We will see what happens today from 12 noon on.