Found at last - The Bat Cave

I noticed this odd driveway on Monday on my cycle home from work.  One of those "did I really just see an old driveway that goes straight into an overgrown cliff" moments.  So I stopped today to make sure.

Indeed - The Bat Cave.  No mansions above it I'm afraid.  I seem to recall this was the block of land that had the (in)famous Tony Abbott billboard before he first came to power (all those years ago now it seems).  Perhaps he was Robin?  He's very fit but surely not of the same ethic as Bruce Wayne?

Oddly, the current Google Maps street view of this address (7 Battle Boulevard - Sep 2018) has "No Parking" signs either side of the driveway.