Looking for approx costs per sqm for a rear extension in the Greater London area. We would like to extend our lounge (shown in green) a bit further to the back and add a WC (shown in blue) as well in this rear extension. The extension will be around 7.5 sqm in total.
https://drive.google.com/file/d/18f9tYySCPXbc3BL3rLEXvpKaZ8Y0oxiP/view?usp=sharing