AFTER A DESIGN BY WILLIAM CHAMBERS, LATE 18TH CENTURY

The chimneypiece pattern relates to a design by William Chambers (d.1796), architect to George III's Board of Works from 1761 and Surveyor-General from 1782; the drawing in the collection of the Victoria and Albert Museum. Another strikingly similar but unattributed design with a central tablet and fluted frieze is held by the Metropolitan Museum, New York.
Chambers worked closely with the the Golden Square sculptor/carver Sefferin Alken (d.1783), who had been amongst the subscribers to Chambers's, Treatise on Civil Architecture, 1759.