Westfield is a private development of 40 houses built in the late '60s by Span and designed by Eric Lyons (sometime President of the RIBA). Span and Eric Lyons worked together from the late `50s to the early '70s, producing a number of widely admired small housing developments in the South London area (other examples are at Blackheath and Weybridge).

Aimed at "young professional buyers with modern tastes" their hallmarks were houses built in a clean, uncluttered modernist style, sensitive attention to proportions and surface textures and the integration of houses into garden settings. Pevsner praised their “careful landscaping, ingenious layout and friendly detailing” Some of Span's ideas were subsequently used by other developers, but seldom with such high quality results.

Westfield is a good example of Span's work. The houses are grouped informally in extensive mature landscaped grounds, off a secluded private road near The Street. The layout insures each house enjoys the maximum quiet and privacy and has an individual rear garden. Garages are in unobtrusively sited blocks. There are also a limited number of parking bays within the grounds, placed to prevent the presence of cars dominating the landscape. Among the other amenities is a tennis court for the use of residents. Inside, the houses are well planned, light and airy, with large windows in all rooms giving views of trees and shrubs.

From the outset, it was considered vital to ensure that the Estate was kept in accordance with the designer's intentions and that its unique environment remained unspoiled for the enjoyment of all residents. To discharge these responsibilities Westfield Resident's Society Ltd. (WRSL) was formed, comprising all the owners of houses on the Estate. Individual owners covenant with the Society to play their part in maintaining the appearance and amenity of the Estate and to pay a monthly maintenance charge, which is agreed at the AGM.