I enjoyed this episode because it was easy to follow, without numerous murders and endless characters /suspects. Glad to report there is no gross incest or sibling sex. The setting was new and interesting (Wales). It was fun to see our man Barnaby in a helicopter. I enjoyed the addition of a sharp young computer-savvy constable, PC Gail Stephens (she will show up in additional episodes).
I mark this episode down somewhat because the two coppers screwed up stupidly and dangerously at the end, with no censure, formal or off-the-books. Instead, Barnaby gave them a thumbs up and shouted "Good job!" Moreover, at that scene, Sergeant Jones acted out of character, being typically portrayed as a clever and conscientious chap. This type of plot contrivance annoys me, sacrificing characterization for plot steerage.
I also found it hard to credit the motivation for murder. I felt the script writer could have done a better job with that.