I've read every page of every issue and Tini does not explain much on-panel in a straightforward way. The issue with the non-British Captains Britain was similar, in that it wasn't clear that everything was happening in an alternate reality until the last couple page. Even then, it didn't feel like a twist, but more of a muddy oh-yeah reveal. Let's not even mourn Captain Jubilee.
Since very little is explained in the text, the well-thought-out explanations on these boards are hard to distinguish from No-Prize winners who explain away mistakes.