This is in the grounds of the former hospital on Banstead Downs, on a by-road to Carshalton. The map location for this is very approximate.
Friends of Surrey Cemeteries (Surrey Cemeteries: a survey, 2012):
Asylum was founded in 1872 – 100 acre farm purchased. Light railway ran from Belmont Station for its construction. Opened 1877. Built in double pavilion style. Architect Frederick Hyde Pownall. Built for 1000 but 1700 inmates by 1881 and numbers rose to 2500 by 1900. Gas works, cemetery and large farm adjoining the asylum. 900 seater chapel and 2 infirmaries.
Patients transferred to Horton 1982. Closed Oct 1986. Main buildings demolished in 1989. Central site now occupied by Highdown Prison.
Visited 2007. Some original site walls remain as do the Victorian farm buildings and several houses. Cemetery (un-named) shown on maps but is now in private ownership and houses a dozen horses. Outline of path within the plot (circa 2 acres) still visible with 5 readable headstones and several others unreadable or broken up/sunken. Now home for about a dozen horses. We spoke to the owner who indicated that other memorials had sunk over time. The memorials included a CWGC stone and a metal numbered marker.