Erection of two-storey extension within rear garden accessed through double storey glazed walkway, closet wing extension at first and second floor levels, replacement of windows with slimline double-glazed units, alterations to front lightwell and entrance area, provision of two condenser units within acoustic enclosure to roof of rear extension, extension of existing third floor dormer window and associated external and internal alterations.

Rear infill extension at lower ground floor light well, replacement of existing dormer roof, lowering floor of vaults and lower ground floor, creating new steps within the front lightwell, new rear French doors to rear courtyard at ground level, part replacement and refurbishment of windows, replacement rear roof light and new roof hatch to central valley and internal alterations, all to alter single family dwelling house (Class C3).

Replacement of front and rear elevation windows with double glazed timber sash windows; replacement of rear first floor with double glazed timber French doors with fixed light above; extension of existing dormer to give additional head height; new lighting and intercom to front door; installation of 2 external condensers within oak enclosure; replacement of lower ground floor rear extension roof; reconfiguration of the lower ground floor extension; new insulation to the roof, above the concrete slab and Aerogel insulation to the third floor and rear extensions for a thermal upgrade; new terrace for the main roof within the existing valley; refurbished chimneypieces; new services throughout; and internal partitions.

Erection of rear extension, formation of lightwell and associated excavation to lower ground floor level; glazed conservatory at rear ground floor level with associated balcony and stair; partial demolition of existing closet wing and replacement with raised roof level; installation of dormer window, roof light and AC units at roof level and associated works. Internal alterations, including changes to planform.

Variation of condition 1, condition 4 (parts a, d, e, g, h, I, j, k) and condition 5 (parts i, iv, v, vii, viii, x) and the removal of condition 4 (parts b, c, f), 5 (parts ii, iii, vi and ix) and 8 of listed building consent dated 3 December 2020 (RN: 20/03709/LBC), which itself varied Condition 1 of listed building consent dated 3 April 2018 (RN: 17/10530/LBC) for 'Alterations to the existing building including removal of existing roof top plant and extension to create an additional storey at fifth floor with tiled mansards and lead clad dormer windows to front and rear; a single storey extension at fourth floor comprising a glazed dome above the existing rear bow; installation of plant at roof level; partial infilling of lightwell adjacent to Gwydyr House; facade cleaning and other facade repair; internal alterations including reconfiguration, fabric removal, and refurbishment works on all floors; refurbishment of meetings rooms, entrance reception and offices; installation of new heating and cooling equipment; provision of a glazed research pod in the library; installation of light-boxes above the central stair and library, and other associated works'. Namely, to allow amendments to the approved scheme that include the installation of a proposed smoke extract system to mechanically ventilate new smoke lobbies to the secondary staircase; the removal of the lift access to the new fifth floor level and associated rooftop overrun; internal alterations at fourth and fifth floor levels; and alterations to ducting at roof level.

Erection of an additional storey on both existing rear extensions, replacement of the existing pitched roof at rear with a mansard roof with addition of a second dormer to the new roof, replacement of the existing dormer windows at the front facade, tanking of the vaults at the front of the property, and internal alterations.

Removal of condition 10 of listed building consent dated 5 February 2021 (RN 20/07404/LBC) for 'Erection of a two storey rear extension at lower ground and ground floor levels with balcony and stairs to garden, lowering of floor to front vaults, new rear dormer window at third floor level, new rooflights at main roof level and erection of rear garden wall'. NAMELY, to remove the requirement of a revised design for the new dormer.

Erection of rear extension at lower ground floor level and associated excavation to lower ground floor level; glazed conservatory at rear ground floor level with associated balcony and stairs; partial demolition of existing closet wing and replacement with raised roof level; installation of dormer window, roof light and AC unit at roof level and associated works. Internal alterations, including changes to planform.

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).

Installation of rear dormer and two rooflights on rear roof slope, replacement rooflight in front roof slope and rear extension as well as internal alterations at second floor level and within roof storey. (Linked with 21/00920/FULL)