We have encountered this scenario at least twice with North York Moors listed planning :-
1. No permission is applied for
2. The change is made
3. A complaint is made
4. A letter comes back from planning,without addressing the full details of the complaint saying no further action will be taken.
5. This seems to occur when a large landowner or builder fails to apply.
So:-
1. Is this a final decision or can one pursue it further?
2. The end result is a shortcut to avoid planning consent unless 'no further action' implies consent when none was applied for in the first place?
3. these decisions don't seem to appear on the planning search engine.