Dirty trick No. 10:- You cannot build two types of extensions at once.

Often a PD extension scheme may also form or be connected with another extension scheme that required formal Planning consent. Most homeowners would use the logic that they can build both extensions as one operation if only for efficiency and reducing costs - this is how the real world thinks and reacts.

No such luck in terms of planning I’m afraid. Building both types of approved and legal PD extensions can interfere and void both schemes.

Suggestion:- Build both schemes separately. To be ultra cautious build the PD scheme first and get that substantially completed before erecting the connecting planning extension scheme. Only in the world of local government could such thinking and mindsets exist to the detriment of normal folk just trying to get on with their lives.