Finished the book last night. It was an enjoyable read and Roberts' little explanatory post-script about how and why he came to read it was also very interesting.
As I said before, I don't read much or any DW novels. But what was quite disconcerting was that as I visualised this one in my head, I kept seeing it with dodgy 1970s DW production values, crap SFX and dodgy monsters. Try as I might, I couldn't superimpose 21st century Who values on it! Seriously!