How can I write the ways this novel sucked? First, the characterization was wrong; the author specifically wrote that it was Romana II in the book, but wrote her so that she sounded more like Romana I.
Second, it didn't read like a Doctor Who story; the author jumped on the zombie craze bandwagon and used that as the villain. It led to some serious disappointment, as they really made no sense in the context of a Who novel.
Finally, it really needed a strong editor. The book jumped around to narrate what various characters were doing quite abruptly; most of the time there wasn't even a page break. It dragged badly in several places and so could have been shored up quite a bit.
Overall, this was not a strong addition at all, and I cannot recommend that anyone read it.