Amalgamation of the ground and first floor maisonette, with the second floor flat, the third floor and part of the fourth floor penthouse to create a single family dwelling house, creation of separate self-contained four bedroom flat at fourth floor level (accessed via 19M Hyde Park Gardens). Demolition of existing extension at ground and first floor, installation of replacement windows at ground, first, second and third floors, demolition of crittal doors and terrace at fourth floor and roof level, erection of mansard roof with dormer windows and parapet, demolition of roof access and rendered chimney and erection of lift motor room at roof level. Internal alterations and refurbishment, including the reinstatement of original features throughout including fireplaces and joinery details, reinstatement of spiral stair from lower ground to third floor, demolition of lowered ceilings, removal of a twentieth century stair and addition and removal of partitions (linked to 20/08322/FULL).