The Harper Collins edition of the Narnia books which I own is in chronological order, which some readers have understandably disputed. But it is a much better edition than the Macmillan paperbacks printed in the published order during the 1970's with their cheap quality paper and cut down illustrations, which were an insult to Pauline Baynes. That was the first set of Narnia book that I owned, which I replaced with the Harper Collins edition a few years ago. It's more important to me to have a set of books printed on quality paper with the complete illustrations than to have them numbered in what is considered by some to be the correct order. At least I now have the complete seven books in a respectable hardcover set. It has all of the original pictures (although not in color), and the text is printed and on fine paper which won't turn yellow in less than ten years.
If it irritates people so much to have the "wrong" numbers on the spines of the books they could have volumes of their set sent off to a bindery and have the books rebound with "Volume One" printed on the outside cover along with the title of
The Lion, the Witch, and the Wardrobe, "Volume Two" with
Prince Caspian, and so on...
Libraries will sometimes have books rebound, but they usually wait for their copies
to wear out first. I think mine will last for a very long time, much longer than that other set of thirty years ago that I gave away.
Larry W.