 The costs of maintaining the property became too much for him and, after undertaking eight years of clearance work in the 1920s, he placed the castle into the guardianship of the state in 1930, with the Commissioners of Works taking control of the property.Archaeological investigations were carried out as part of the clearance work by H. Honeyman in 1929, exposing more of the main gatehouse, and further work was carried out under Robert Bosanquet in the 1930s.Aerial photography was carried out by Walter de Aitchison for the Ordnance Survey.