One of the comments here will tell you what's technically wrong with this episode.
As someone without the info provided by that viewer, I thought this was pretty good. And I'm surprised I like Scott as much as I do.
When an elderly member of the Midsomer Malham Orchid Society is murdered, Barnaby and Scott are on the case. She may have looked like an elderly woman, but Madeline Villiers, the victim, had quite a sex life according to her journal, and it looks as though she was selling very rare orchids for beaucoup bucks.
Then someone else from the society dies, and his entire orchid collection is ruined. His wife explains to Barnaby and Scott that orchid growing is an expensive and addictive hobby. So, it seems, is murder. There are many people to be investigated, including a mysterious man from China who was in some way involved with Villiers.
I enjoyed this episode and got a kick out of the relationship between Barnaby and Scott, which is much more relaxed than it was originally, and Scott seems to be liking the job more.