Given the following context:

The commission for the brand new house of Knightshayes Court was obtained from Sir John Heathcoat-Amory in 1867 and the foundation stone was laid in 1869. By 1874, the building was still incomplete, owing to ongoing difficulties with Heathcoat-Amory, who objected to many of Burges's designs on the grounds of cost and of style. Although work had begun on the interior, the turbulent relationship between architect and client led to Burges's sacking in 1874 and his replacement by John Dibblee Crace. Nevertheless, Knightshayes Court remains the only example of a medium-sized Burges country house, built in a standard Victorian arrangement. Early French Gothic in style, it follows a standard neo-Tudor plan of a large central block with projecting gables. The tower Burges planned was never built.
The interior was to have been a riot of Burgesian excess but not a single room was completed to Burges's designs. Of the few interior features that were fully executed, much was altered or diluted by Heathcoat-Amory and his successors. However some of the interiors, such as the library, vaulted hall and the arched red drawing room, remain or have been re-instated.Since the house passed to the National Trust in 1972, major works of restoration and re-creation have been undertaken and a number of pieces of Burges furniture, mostly not original to the house, are displayed. These include a bookcase from Buckingham Street and a chimney piece from the Hall at Worcester College, Oxford, where, in the 1960s, some decorative works by Burges were removed, although his redecoration of the college Chapel remains. The aim is, as far as possible, to reinstate the work of Burges and Crace.

answer the following question:

Along with Sir John Heathcoat-Amory, who altered and diluted the interior features of the house he commissioned in 1967? 

his successors