This was the final episode for Diana Rigg, playing Mrs Pumphrey. Rigg died in 2020 and her part was recast in the second series with Patricia Hodge.
The title is a play on words. "A tricky case" is an old saying, the respelling of "Tricki" in reference to the dog that is the tricky case in this instance.
With an audience of 4.81 million viewers, this was the least watched episode of the first season.