I found this a really enjoyable episode, it features a good, clever mystery, it has some wonderfully humorous moments, plus it contains some fine performances.
It's one of the best openings to an episode I can remember, classical music is always a great choice, and the Pearl Fisher's Duet complimented the dramatic opening scenes beautifully.
The acting is top notch all round, but it's the two veteran actors, Sam Kelly and Julia McKenzie that stood out for me, both utterly wonderful, funny, but serious when needed.
I've knocked two points off because I thought the identity of the killer was a little too obvious, but all in all it's a very good episode. 8/10