Benjamin Haydon and Charles Rossi - Rossmore Road, London, UK - Blue Plaques on Waymarking.com

The Encyclopaedia Britannica website has an article about Benjamin Haydon that tells us:

Benjamin Robert Haydon,  (born Jan. 25, 1786, Plymouth, Devon, Eng.—died June 22, 1846, London), English historical painter and writer, whose Autobiography has proved more enduring than his painting.

The son of a Plymouth bookseller, Haydon went to London to attend the Royal Academy schools. He first exhibited at the Royal Academy in 1807, but because of subsequent quarrels most of his later paintings were shown at private exhibitions. Haydon’s ambition was to become the greatest historical painter England had ever known, and he went on to produce a series of stiffly heroic canvases on such biblical and classical subjects as “The Death of Dentatus” (1809), “The Judgment of Solomon” (1814), “Christ’s Entry into Jerusalem” (1820), and “The Raising of Lazarus” (1823). His depictions of the contemporary English scene in “Mock Election” (1827) and “Punch or May Day” (1829) show flashes of humour, however, and his portrait of “Wordsworth” (1842; National Portrait Gallery, London) is an incisive character study.

Haydon’s financial incompetence and disappointed artistic ambitions finally ruined him. He was constantly in debt and eventually committed suicide.

His stormy career, down to 1821, is recorded in his Autobiography, which, with a selection from his journals covering the rest of his life, was published in 1853. The complete text of his Diary was published 1960–63. Haydon’s acquaintance among literary people was extensive, and intimate glimpses of celebrated individuals enliven his writings, for he had a keen eye for character and a striking gift of phrase. Haydon wrote the article on painting for the seventh edition of the Encyclopædia Britannica, and his Lectures on Paintings and Design was published in 1846. Though sternly committed as a visual artist to a Neoclassical ideal (embodied in the Elgin Marbles that he so admired), Haydon inadvertently wrote a masterpiece of self-revealing Romantic autobiography.

The Speel website has an article about Charles Rossi that advises:

The sculptor J. C. F. Rossi was born in Nottingham, his father being an Italian doctor. He studied sculpture under Locatelli, worked at the Derby China works, briefly for Vulliamy, then for the Coade manufactury. In 1781 he became a student at the Royal Academy Schools, exhibiting there for the first time in the following year, and on winning a travelling scholarship, spent three years in Rome. After his return to London, he formed a partnership with a mason-sculptor called J. Bingley, and drawing on his early training in terra cotta, made a variety of terra cotta and stone statues (much later he worked on terra cotta with J. H. Bubb). He flourished in the 1790s, winning commissions for architectural sculpture on important buildings, and designing four monuments in St Paul's. He was elected ARA in 1798, and RA in 1802. Over the course of a long working career, he managed to produce 16 offspring, by two wives, and of these three at least became sculptors – Henry Rossi in London, Frederick Rossi, and Charles Rossi, who became a monumental mason and went to live in Barbados. Rossi himself stayed in London, lodging for a period with the well-known painter Benjamin Hayden, in a modest house off Lisson Grove in Marylebone.

Rossi’s typical style in his monuments and elsewhere, is draped or semi-draped classical figures, slender and refined looking with elegant long necks, somewhat recalling society pictures by Sir Thomas Lawrence. The faces are often rounded in a way which dates them firmly in the early rather than the later 19th Century, and there is a tendancy, as with 18th Century pictures, to have a female figure looking heavenwards. Otherwise, his female figures are moderately full in figure, rounded in the breast, slender in the arm and with long, expressive hands. There is a nice pair in this vein on the front of the Royal Opera House, London, depicting Thalia and Melpomene - these I believe to be to the design of Flaxman - and the Melpomene has his signature on the base - but it seems that Rossi was involved in the actual carving. Another pair are in Leicester – Music and Dance on the front of the City Rooms, and these are signed by Rossi and Bingley, though I understand that Rossi was the primary artist for these works. His St Paul's monuments are Cornwallis, Faulkner, Moss and Riou, and Rodney, all active in the war against Napoleon. His work also includes reproductions of classical works, including the four caryatids for St Pancras Church on Marylebone Road.