Katherine Margaret Riddell (died 1961) (d. 1961) Parents Sir John Buchanan-Riddell, 11th Baronet Sarah Isabella Wharton Children Margaret Olive Charteris Anne Louisa Charteris David Nigel Charteris John Douglas Charteris Siblings Dorothy Isabel Riddell Olive Frances Riddell Sir Walter Riddell, 12th Baronet Partners Nigel Keppel Charteris