There has been a bit of a kerfuffle about Midsomer - no non-white characters, which is not realistic. Every small town and some large villages have at least a Chinese takeaway! The producer had to resign after he defended his position as deliberate. I think one black face was once seen on a bridge in the background.

Another good mystery series is "Pie in the Sky" in which a detective wants to retire and run a restaurant, but is forced to stay on for special cases. It does have a more realistic spectrum of characters, while maintaining overall Englishness.

Penny