u/Kiwi8962

We are building retaining wall next to our unused driveway. Max height of retaining wall is 800mm and the going down to 200mm in approx. 3m. The other side of this driveway is another neighbour's driveway. So 3000mm (our) , 250mm ground, 3500mm their driveway. Contractor suggested leaving 200-300mm gap from retaining wall fill in with scoria and coil at bottom. Any suggestions how else I can ensure it's done correctly to the standard? Thanks