Well, B.D., I’m glad to have that settled. As I said at the time, I was open to being persuaded if more evidence or better arguments were presented. Now that new evidence has surfaced, I’m content. (Although I continue to think McGrath jumped the gun by demanding we change the date based on the much shakier evidence he had in hand at the time.)
Several commenters on my original blog post wanted to know why this question matters. Andrew offers a few opinions on that, but to be blunt, my own view is that it matters because getting the facts right is important for its own sake. I believe no one would have championed that view more ardently than Lewis himself.
Speaking of getting the facts right, I have to offer a correction to your post. You write that opposition to placing The Lion, the Witch and the Wardrobe first in order is “heresy.” It is actually blasphemy. Heresy involves disputes over points of doctrine, whereas blasphemy is an act that profanes the sacred.