We can't use Landgate data, their data is copyright and not compatible with OSM's licensing requirements.

We can use the Main Roads WA data which is CC BY and which we have a waiver for. We even have it as a background imagery layer in JOSM and overlay imagery layer in iD, all out of the box.

In that dataset it's Coyrecup for the southern section only, then Simper from the junction with Coyrecup North Road.