To filter by council ward within the Planning Applications tool:
From the Control Centre select 'Ward Boundaries'.
Also from the Control Centre click 'Planning Applications'.
Click the bar at the top-centre of the map where it says 'Search as I move the map' and select 'Draw custom search area'.
Draw the area correspondent to the ward boundaries of the council of your choice.
The results will show on the map and on the left side bar.
You can also save your search by clicking 'Save 💾 ' or export all the results to your email in CSV format by clicking 'Export' on the left side bar.