This sweet miniature purports to show Charlotte St.John (d1801), daughter of the 3rd Viscount Bolingbroke.
The miniature, described (and pictured) to be in a red leather case at the time of its sale in 2015, was subsequently remounted in a gilt frame and resold.
The accompanying label (shown above) identifies the sitter but is misleading.
George Richard St.John, 3rd Viscount Bolingbroke, had only one daughter by his first wife, Charlotte Collins. The girl's name was Mary and though it is possible she may have been called Charlotte after her mother, she died in June 1804 and not in 1801. The 3rd Vsct. Bolingbroke had a sister named Charlotte, but she died in infancy in 1762.
There is therefore a question mark over the identity of the girl in the portrait though most likely it is a St.John family member.