I don't think I ever expected one of the Rivers-books to take place outside of London. The city always played such a prominent part that I couldn't expect Peter solving crime somewhere else. Well, but he did and it worked (thankfully without turning Peter too much into 'city boy who has no clue how the countryside works and complains constantly'. I feared that at first after remembering his comments on London vs. anywhere else in the previous books but it was pulled off in a way that made it clear that Peter is unfamiliar with the situation but didn't act like an idiot).
Sadly, not being in London also means a serious lack of Nightingale, Molly, Toby & co. I missed them a lot and even though some of the newly introduced characters were awesome as well (I hope we hear from a few of them again) they just couldn't replace them.
The case itself was very good and definitely among the better ones of the series, just the ending didn't overwhelm me. Something major didn't get anything that came close to a satisfying answer and something else was tied up a bit too conveniently and quickly.