The rather excellent Mystery at Stowe by
Vernon Loder (aka John Vahey)
could be the perfect Golden Age detective novel: its set in a nice country house in late 1920s England, bumbling police are set right by the keen amateur (although he apparently has some detective work before while administering the natives in some far flung corner of the Empire) and the murder weapon a mysterious artifact of the tribes from South America...
In fact it could almost be too much, in the hands of a less skilful writer it could easily have descended into self-parody but Loder produced a fine work here with some interesting detective work. Maybe it falls down on the final reveal, being a bit implausible. But then again that wasn't exactly an uncommon Golden Age trait either.
