A wild guess is the winery district of McLaren Vale up near Chalk Hill Rd somewhere.
Not McLaren Vale. It is in Adelaide Hills bicycle-riding country, and is a nice (and quiet) bitumen road.
For some help, it is within 5 kms of Mylor as the crow flies.
Well, the vegetation suggests dry uplands, either south of Hahndorf or SW of Mylor. I'm sure I've seen this thing before but I don't generally take note of tourist magnets so no real idea where it is.
So maybe Bradbury Rd.
Getting close, not Bradbury Rd but in the area. It is a hilltop, and it visible on GSV.
Thought I'd seen it before but it's not on one of my regular routes. Red Hill Rd approx. 100m west of Longwood Rd. Link.
Behind (i.e. east side) of Harbour Town, (West Beach / Adelaide Airport)?
No, nowhere near Adelaide Airport.
Airport I thought it might be, Parafield though - along the path (beside the trainline) connecting Mawson Lakes and Salisbury.
That's the place. Lovely smoooth new surface, almost soporific riding along there, I had to take a break to snap a happy.
Except that parts of their lovely new surface laid last year already have tree-root uplift.