Mr Powell is unknown, but Bolton has suggested that he may have been John Powell (d1783), a clerk of the Pay Office. In 1779 a Mr Powell commissioned the Adam office to design a garden building. There also survive two drawings giving a design for a house for Powell, which is presumably also datable to that year. The intended location for these designs is not known, and they are not thought to have been executed.

Literature
A.T. Bolton, The architecture of Robert and James Adam, 1922, Volume II, Index pp. 57, 84; D. King, The complete works of Robert & James Adam and unbuilt Adam, 2001, Volume II, pp. 121, 227

Frances Sands, 2015