Conversion of existing single-family dwelling into 4 dwellings (1x 1 bedroom flat at basement, 1x 2 bedroom flat at lower-ground floor, 1x 1 bedroom flat at ground floor level, and 1 x 4 bedroom maisonette at first to fourth floor), including new bathrooms and kitchens, and an extension at rear lower-ground and ground floor level including roof terrace at first floor level, erection of an extension at roof level and installation of new windows and doors to the rear elevation.