Townhill Farm became part of the Manor of South Stoneham, but was purchased in 1787 by Nathaniel Middleton, who had made his fortune in the service of the British East India Company.

In 1912, extensive further modiciations were made to the building by architect Leonard Rome Guthrie, who returned after the First World War to add the music room and a boudoir for Lady Swaythling.

[2] The gardens at Townhill Park were laid out by Gertrude Jekyll and were noted for their rhododendrons, azaleas and camellias.

294 acres (1.19 km2) were sold to Southampton Borough Council for housing, and the suburb of Townhill Park came into existence.

Meanwhile, the house itself and the remaining 30 acres (120,000 m2) of land became a school for underprivileged girls, owned and operated by Middlesex County Council.

The north elevation is stuccoed and has five bays of sash windows, with the central three breaking forward under a pediment with a blank cartouche.

[5] The south face is similar to the north, with the differences that there is a sundial set into the pediment and the arches on the ground floor have triple-round heads with Tuscan half columns.

[7] The music room that was added after the First World War is now used as a main hall, and retains its original polished walnut panelling.