Reginald Hill's final novel--not to be published?

I received an e-mail this morning from Amazon.co.uk, which said that Reginald Hill's final Dalziel and Pascoe novel (still untitled) was "no longer available." There's no official word from Hill's publisher, Harper Collins, about the book's fate.  It would be hardly shocking if there wasn't enough manuscript to bring out--the book's release had already been delayed twice--but I'm sorry if we're not going to have one final adventure.