[1] There is a Thomas Jackson recorded in the 1855 electoral roll as living in Mount Grove House, Hampstead. However, there are several men with this name in this area of London.
[2] Flatou (1820–67) was a Prussian-born London-based art dealer. Very little is known about him as a person or his activities. There is speculation that he was illiterate, as no handwriting sample survive; it appears his wife did most of his correspondence. He died from dropsy (now known as oedema) in 1867. See https://www.artmarketstudies.org/research-by-harry-dougall-louis-victor-flatou-1820-1867/
[3] Dunbar was a prominent London shipowner. His vessels were used for transporting troops during the Crimean War and also convicts to Australia. Dunbar’s will has been transcribed here by a descendant as part of a talk about him: http://www.merchantnetworks.com.au/periods/1800after/1800dunbar.htm
[4] Catalogue of the highly important collection of modern pictures formed by Duncan Dunbar, Esq, deceased, of Porchester Terrace…, Christie’s, London, 5 May 1894 (Lugt 52574), accessed https://archive.org/details/higduna00chri
[5] See Register of Inward Correspondence and, Registered inward correspondence, National Gallery of Victoria, 1894, letter no. 1157, held at Public Records Office of Victoria, VPRS 800 and VPRS 805.
Exhibited: Royal Academy, London, 1851, no. 14