Mary Clark married Claude Champion de Crespigny, 16 Feb 1764, at St. Giles, Camberwell. The diary entry for 16 Feb 1791 (fol. 18v) refers to their 27th wedding anniversary. They had one son William (bap. 1765) who married Lady Sarah Windsor, daughter of the Earl of Plymouth in 1786. The diary entry for 8 July 1791, refers to the return of William and his wife from abroad, and the christening of their third child, Augustus James on 23 July 1791 (St. Giles, Camberwell). When this diary was first catalogued, it was remarked that ‘the diarist refers to her husband throughout as “Starke”, which is puzzling, as there does not seem to have been a familial connection with the Starkes of Epsom’. The reason for this has been discovered by deciphering the shorthand notes which supplement many of the entries in the diary. It appears that Mr Starke is in fact Mariana Starke’s younger brother, Richard, and the shorthand notes reveal that Mrs Crespigny had formed a romantic liaison with him. The shorthand notes provide a brief picture of a sometimes stormy relationship. The short entries each day in plain text describe her social engagements and Richard Starke’s movements. He was regularly on duty with the Life Guards (see Bibliography). They often visited Mariana Starke's family at Epsom and were frequently in the audience at her new play, 'The Widow of Malabar'. Mary Crespigny was a patron of the arts and had a private theatre in the grounds of her house at Camberwell. She was also a keen archer and there are a number of entries relating to the Epsom archery and target shooting at Boxhill. There are also weekly accounts. The printed matter at the beginning and end of the diary includes a list of notable days, the latest country dances, beauty and health recipes, and tables for calculating finances. Some of the printed matter (fols. 71-5) has been cut out.

The shorthand code was deciphered by Jim Clover OBE using a blend of technical and manual processes.