Mansel And Chandos

Eight listed "'Chandos' Books" by Dornford Yates feature and are narrated by Richard Chandos.

Chandos also narrates a ninth novel, Ne'er-Do-Well, and appears in a tenth, Gale Warning.

Thus, for present purposes, we can refer to ten Chandos books.

Jonathan Mansel is:

"'Jonah' in Yates' ten "'Berry' Books" and in one other "Berry" short story, "Letters Patent";

"Mansel" in eight of the ten Chandos books and in two other novels, Shoal Water and Gale Warning.

Mansel's and Chandos' antagonist, "Punter," appears in the related novel, Safe Custody.

The ninth and tenth 'Berry' books and "Letters Patent" are set in an alternative continuity, where:

Mansel's cousin, Boy Pleydell, the narrator of the 'Berry' books -

has, like Cecil William Mercer (Dornford Yates), worked as a barrister;
thus, has not always been a "man of leisure";
wrote the "Dornford Yates" books, including the Chandos novels, as works of fiction under that pen name.

Addendum: Boy was also a barrister in The Berry Scene.