Hack off all the plinth to just above the air brick height all the way round or cut the render back to 40mm to 50mm above ground level.
Rake out the beds and perps to about 20mm to 30mm and use a 3:1 mix of any sand and cement to point.
Rake out the beds and perps to about 20mm to 30mm and use a 3:1 mix of any sand and cement to point.