Thanks BrianHerps & WillO. I looked at the key in Cogger, and decided that the suggestion of dark grey markings on the throat (didn't get a proper picture of the back or throat unfortunately!) sent it in the direction of E. heatwolei.
The two key features for separating them are - in tympanum - a pale anterior edge to the ear opening and the absence of a reasonably prominent pale stripe along the side of the head. Cheers Will