For those unfamiliar: Diana Rigg is Mrs. Bradley, a wealthy, long-divorced woman who is slightly notorious for helping out and lecturing to the police (she has written on psychology, toxicology, and prison reform). She dresses sensationally, makes acerbic remarks constantly, and frequently makes asides to the camera. Like any fictional detective, people have a tendency to get murdered around her, and she investigates the crimes with the help of her chauffeur, George Moody (Neil Dudgeon), who is twenty years her junior but seems to be mildly jealous of Inspector Christmas (Peter Davison), who is closer to George's age than Mrs. Bradley's but nevertheless flirts with her constantly. For her part, Mrs. Bradley is warm to both of them, and occasionally maneuvers circumstances so she can see George very much out of uniform. In the interests of justice, of course.
The characters are warm and witty, and the mysteries are nothing fancy -- they're rather strained at times, actually -- but they're fun, and it's definitely an enjoyable dynamic, suitable for ripping off or updating (the series is set in the 1920s or 30s). It's a very nice cup of tea.