While I am happy to go with duperreyi, seeing as how you had it in your hand the two features to confirm Acritoscincus duperreyi are the which scale row the cream dorsolateral stipe is on and if the frontoparietal scale is single or divided. Neither are obvious from this image. If you can confirm the undivided frontoparietal scale that would be useful.
Based on the image and locality I am happy to go with Pseudechis but the image is not conclusive and too far away to see any useful detail, so happy to stand corrected.