Various.

According to the Post Office London Directory Charles Douglas Singer was in 1859 secretary to the Medical Invalid and General Life Assurance Society. By 1880 he was described as a letter clip manufacturer. He lived in several of the North London suburbs, from c. 1859-67 in Upper Holloway, from c. 1869-82 in Stoke Newington and by 1889 he was living in his brother George's home at 53, The Common, Upper Clapton.

Catherine Sarah Courtenay of Porterlington, Queen's County, Ireland mortgaged property to Charles Douglas Singer in 1860. These papers concern the legal problems and the incumbrances on the estates in which she had an interest, either through her husband John Courtenay who died in 1841, or inherited from her father George Murphy.

The Harrison family papers relate to Edward Harrison who died in 1865, a stationer presumably of Matthews Harrison and Sons Ltd. of 82, Cornhill; his widow Elizabeth who lived at Tulse Hill and Blackheath before moving to Eastbourne and the younger Edward Harrison who lived in Enfield from 1891 until his death in 1902 or 1903. It seems possible that his wife Emma was the daughter of Charles Douglas Singer who was made a trustee and executor of his will in 1891. In her will she in turn appointed two members of the Singer family trustees and executors.