It seems Anne Dorothy Monckton was third cousin of the 1st Viscount Monckton.
A look at the Carder-Geddes family:
Gillian R. dau. (with a brother, Geoffrey) of Reginald Carder-Geddes (1904-2002), of York, formerly of Croydon, Surrey, and (m. 1930) Sybil Dorothy, dau. of - Barnett.
Reginald C.-G. elder s. (with a dau., Elsie Naomi) of William Henry Carder[-]Geddes (1880-1959), of 4, Picardy New Cottages, Picardy Hill, Belvedere, Kent, carpenter and joiner (inc. for a lift manufacturer) and (m. 1903) Edith Constance (1881-1953), dau. of William Henry Markham (1853-1882), of 72, Crampton Street, Newington, sign writer.
W. H. C.-G. appears in the 1881 census at Southwark alongside his mother, Emma (1855-), listed as 'wife of ship's steward'; William's 1903 marriage certificate (viewable, with much detail on this and related families, here:
http://www.lyons-family.co.uk/Andrews/1820-andrews-charles/children-charles-andrews/frances-1849/frances-1849.html ) gives his father as 'William Joseph Carder Geddes', 'chief ship's steward'; there is an 1878 marriage of William Joseph Geddes and Emma, dau. of Henry Dolly. There is an Emma Dolley, b. 1855, daughter of Henry Dolley, born at Lambeth in the 1861 census; her father is a coach trimmer, of Tower Street, Southwark. The marriage record also gives William Joseph Geddes's father as William Geddes. There are several possibilities in records from this point onward; I tried a marriage between William Geddes and a Miss Carder but didn't find anything. Perhaps this took place in Scotland or, of course, elsewhere.