HCR diary 24.11.1821 party at Aders "Also a Mr Harcour (or some idem sonam) who is said to sing well and has a modest and sensible air"
29.11.1822 at Aders "Mrs Harcourt a niece of Aders was just arrived - a very plain woman but she looks amiable and Mrs A: says she is accomplished"
HCR diary 10.11.1817 "I stayed with Aders till late and gave him directions to buy a number of engravings for Mr Gurney"
Probably? Hudson Gurney (DNB 1775-1864)
HCR diary 1.7.1842 at Samuel Rogers' breakfast table "Mrs Forster daughter of Banks the sculptor"...."and her daughter Mrs Poinder"
Edward Forster (DNB 1769-1828) writer married at St George Hanover Sq on 3.8.1799 Lavinia Banks. Emma bapt 20.5.1801 St George Hanover Sq dau of Edward & Lavinia Forster, married at British Embassy Paris 26.12.1832 Ambrose Poynter (DNB 1796-1886) architect. She died 1848, Lavinia nee Banks may have married again? (Lavinia Forster marriage index 1837 Kingsclere Hants).
HCR diary 13.1.1819 Mrs Opie / Fuseli / Sidney Smith / Samuel Rogers (I just made that note with no more context)
4.4.1823 after seeing Aders' pictures, Sir George Beaumont "proposed bringing Fuseli"
George Beaumont (DNB 1753-1827) and Henry Fuseli (DNB 1741-1825). I've no idea whether Fuseli did visit Aders' collection
HCR diary 8.6.1828 "called on Aders - a Mr Goldschmidt was with him, who took us to see some fine paintings on sale in Leicester Square, belonging to Signor Reghellini di Schio"
4.11.1833 "went to the Aders - an agreeable evening there - Mr Goldschmidt was there - He has proved a very generous friend"
Possibly Adolphus Goldschmidt?
HCR diary 10.4.1844 Robinson called "on Mrs Gent (a miniature painter) a friend of Mrs Aders for whom a letter was brought by Stansfeld from Mrs A: and by me strangely forgotten. I lately found it, thinking it had been put in the post - I called on her today and delivered it with an apology. She seems an agreeable person (6 Tavistock Street, Bedford Square)"
HCR diary 17.5.1841 "Ellen seems to be recovering herself - she is under the protection of Mrs Fry!"
This was very likely Elizabeth Fry (DNB 1780-1845). Mrs Aders' daughter Ellen Ley (1804-1867) had previously been arrested for theft (see HCR diary 7.1.1840)
HCR diary 5,4,1823 musical party and supper at Aders' "This party I had made for them. Wordsworth, Monkhouse and the ladies, the Flaxmans, Rogers, Coleridge, Mr & Mrs Gillman were my friends. Besides the Reeces and other musical party"
16.6.1826 "Mrs Mont: and Mrs Aders met at Gillman's - they shook hands. Ich dachte dass Mad Aders sich herabliess - sie wäre gewiss froh wenn Mrs M: sie besuchen wollte"