Change of use of single dwelling to 1no. 1 bed flat and 1no. 3 bed maisonette flat, including erection of two storey rear extension with bay window to second floor at rear, installation of 1no. rooflight to rear roof slope, excavation works to extend basement, reinstatement and replacement of windows, installation of 3no. windows to side elevation, erection of metal railings to front and rebuilding of rear garden wall, following demolition of rear extension.