H D Thielcke’s father was Johann Daniel Thielcke and his mother was named Anna Elizabeth or Anne Elizabeth. We thought at first that she was from high class German descent but Peter Sabor of McGill University has stated that she was British. Here is what he sent me:
«I’m appending here my note on Mrs Thielcke in its current state. I’m pretty sure that she was _not_ the aristocratic German Anna Elizabeth, who would surely not have married a rather lowly Court groom, as Johann Daniel Thielcke seems to have been.
Mrs Papendieck, whom I cite here, is the source for the idea that Mrs Thielcke previously worked for Princess Augusta (d. 1772). If that is correct, she must have been born not much later than 1750, so she might well have been several years older than her husband. She would have had three children in her 30s, and Henry Daniel might have been the last; perhaps after him her childbearing days were over. But this is just guesswork, of course; I still hope to find her dates through the Royal Archives at Windsor.
Mrs Thielcke turns up repeatedly in Fanny Burney’s Court journals, but always just passing references to her, such as “Mrs Thielcke was present.” Never any interesting details. But there is a bit more on her in Mrs Papendiek’s gossipy journal, including an interesting story about her devotion to Queen Charlotte.
 Anne Pascal, the Queen’s wardrobe woman, m. c.1780 Johann Daniel Frederick Thielcke (1760-1830). She had served as dresser to Princess Augusta, mother of George III, until Augusta’s death in 1772. This service, according to Mrs Papendiek, made her disliked by the Queen, who considered her ‘as a spy upon her actions’ (Court and Private Life in the Time of Queen Charlotte: being the Journals of Mrs. Papendiek, ed. Mrs Vernon Delves Broughton (London: Bentley, 1887), I, 10).
She was at a lower level of employment than FB and received only £30 per annum, compared to FB’s £200 and Mrs Schwellenberg’s £137. She was responsible for more menial and intimate tasks, including assisting the Queen with her undergarments and corset. She had a daughter and two sons, one of whom, Henry Daniel Thielcke (1788-1874), became a portrait and history painter and engraver who painted many portraits of the royal family; see Ross Fox, ‘Henry D. Thielcke: A recently Found Portrait and some Reflections on Thielcke’s Links with the English School’, Annual Bulletin, National Gallery of Canada, 8 (1984-85): 1-6. »
Anne Elizabeth Thielcke married Johann Daniel Friedrich Thielcke in 1782, according to archives.