The spaceman in issue 22 is Dream
They bear a strong resemblance to Morpheus (skinny, pale, scruffy black hair - a few panels even have them with all-black eyes) and it's not hard to imagine Morpheus would want to visit a place that draws so much on religion and mythology. Miracleman will eventually be killed by the Fury
Now that series is owned lock, stock, and barrel by Marvel Comics, there's no reason to distinguish between the original Marvelman and Marvel's own version, Miracleman — especially since Marvel was the reason that the original had to be renamed. If true, then this series takes place on Earth–238, and the end result of Miracleman's utopia was shown way back in 1981: the entire planet was murdered by the Fury.