Thorn is listed Grade II.
Early 19C house on an older site; a later extension along the main terrace wall was subsequently demolished. In 1920 William Arkwright brought urns from Sutton Scarsdale Hall to enhance his terraced garden and the design reflected his previous house, including the rose garden and the gateway at the far end of the main terrace. After his death in 1925, Mrs Sebag-Montefiore continued to plant rare specimens, some of which are now champions. The Gibsons have splendidly restored and enhanced the garden since 1981, despite massive storm damage in 1990. The drive leads to a formal circle in front of the house. Long terraces run parallel with the river from the conservatory at the back of the house. The slopes below and above these are planted informally but choice and tender species are found throughout.