E-flex is available at Caltex on O'connel st, North Adelaide. I grabbed a few L into my jerry can for some testing. Using this method I calculated it to be ~72% ethanol, or ~E72.. My crude test lines roughly up with Caltex's claims of being E70 atm.
Tempted to test it in my car, but since my T518z is maxed out, I don't think I'll be netting a power increase of any more than 5%. Well, only one way to find out!