John Dickson Carr
John Dickson Carr was a very highly regarded American mystery writer, though he lived for most of the '30s and '40s in England, married there and set many of his books there (<a href=https://en.wikipedia.org/wiki/John_Dickson_Carr>Wikipedia</a>). His two main detectives, Dr. Fell and Sir Henry Merrivale, were very English (<a href=https://en.wikipedia.org/wiki/John_Dickson_Carr#Dr._Fell_and_Sir_Henry_Merrivale>Wikipedia</a>).