This is Lot 8 in a brochure for the sale of the Pilton House estate in 1849 by James White. It refers specifically to Westaway House, "a comfortable residence seated upon a lawn, with excellent walled garden, yard, coach house and stabling and a plot of land in front of the house".
It can be seen just above the centre of the map of the estate - follow this link: http://vimp.thepiltonstory.org/picture/Plan-of-the-Pilton-House-Estate-s...
Thanks are due to Louise Thomas, Manager of Pilton House, for showing us this historic document.