Single storey rear extension

Single storey rear extension no greater than 4.00 m in depth, 3.00 m high with an eaves height of 3.00 m

Its a 3-bed semi-detached house in Maidenhead. Further, it includes a 4 meter deep rear extension on the ground floor and want to have an open plan kitchen, dining and living area. We have applied his application through prior approval route and got his application decision within 6 weeks. Attached are his council prior approval decision and project set of drawings.