I think you'll find a lot of authors are starting to bring out short stories/books etc in Kindle format which may never appear as paper books. Though in this case it is published by Constable and Robinson rather than the author herself. There are any number of books which may never appear as e-books so I see nothing wrong with having it the other way round as well.
Did you know you can download a free app for your computer/phone/tablet so that you can read e-books without buying a Kindle?
Thank you, Bob. Thank you, thank you, thank you! I have collected all Agatha's books since she first appeared on the scene, and as I could find no reference to a HB/PB edition was beginning to think that this 'Agatha Raisin and the Christmas Crumble' might only be available as a kindle edition. Horror of horrors - I am not into kindle and resolutely never shall be, and the sight of me starting to hyperventilate distressingly at the thought of never being able to read this forthcoming edition was not at all pretty - until I read your very reassuring note. Again, thank you!