It was listed by Fine Antique Mirrors. Sold pieces stay on Sellingantiques as a record of what has passed through, and the next one is rarely far away.
Fine Antique Mirrors has dated this Regency Convex Mirror to the 1800s.

Original wafer thin convex mirror plate, which has a shallow convex curve and overall foxing. Plate re silvered most probably in the late 19th century.
Original backing board, complete with T. Fentham makers label.
79 cm diameter or 31 1/8" diameter.
Thomas Fentham
Trading at 49 Strand (1777); no. 52, ‘opposite Old Round Court’ (1778–93); no. 51 (1784); and 136 Strand, near Somerset House (1794–1820).
Fine Antique Mirrors has dated this Regency Convex Mirror to the 1800s.
Specializing in antique 18th/19th century gilt mirrors. Gilding restoration undertaken.
You can view the stock and full dealer information on the Fine Antique Mirrors Profile Page