Ha ha, yes of course.... Personally, I was really surprised by a March date... There's probably been a bit of grumpiness in the marketing and sales teams over that one. I would have had it down as a slam dunk xmas title rather than a holiday read but hey ho... It'll sell (eventually) anyway.
Likewise.
However, the only reasons I can think of for the delay, are final editing stuff (and rewrites) to be carried out by Hilary Mantel, or ill health (possibly requiring a procedure) - she has been plagued by physical ill-health - suffered by the author.
But, yes, agreed: A Christmas date of publication would caused sales to further soar - anyone who has a friend or family member who likes history, historical fiction, - someone like me, in other words - would have a guaranteed winner of a present.
Moreover, the book trade can see up to 80-90% of their annual sales around Christmas, so it would make enormous sense to publish The Mirror and the Light then; the whispers I heard around a month ago were thinking in terms of a December release.
And agreed, too, that the marketing and sales teams could well be a bit grumpy.
Now, it'll certainly sell - but maybe not in the numbers it would have, had it been published in December.
Bear in mind that each of the two earlier books in the trilogy (Wolf Hall and Bring Up the Bodies) won the Booker Prize.
Mantel will want to bring this one home in style - it is the work she will be judged on and remembered for.