[1] The property is named after Sir Robert Fitz-Neil whose family held the estate until 1386, but the oldest part of the current building dates back to the house probably built by Sir John Iwardeby in the early 16th century.

[2] Iwardeby's original house was probably similar to the “Bayleaf” farmhouse[3] at the Weald and Downland Open Air Museum.

In the early 17th century with the rest of the original house either demolished or otherwise destroyed the remaining solar wing was extended to the west by the addition of a structure with the three distinctive gables.

[2] Fitznells continued to function as a farmhouse well into the 20th century; when bought by S. E. Parkes (Modern Homes & Estates) in 1927 from the Gadesden family the estate still included 125 acres (0.51 km2) of land, farm buildings and five cottages.

Additional buildings to the south of the main house were added on the site at this time.