Oh, my good Lord.
To be honest, I may be unfairly downgrading the content, because I listened to an audiobook, whose narrator had adopted an accent that ranged Brooklyn to Cockney, by way of Ireland, Scotland and Australia, and I found it hard to stop laughing. Through the laughter, though, I did seem to find many anomalies and anachronisms, such as a southern English 1920s aristocrat adopting the Liverpudlian slang "bizzies", and his son referring to him as "guvnor".

The story is engaging enough, as a light, sub-Christie piece of froth, although filled with implausible developments, mostly about the family's willingness to allow the protagonist to nose into their life.

I can't see me bothering with others in the series.