This seems to be a significant sighting, a Tree Goanna just inside the ACT and unlikely to be ex-captive. Species now almost extinct now in the ACT. It is ~15km from the known Tree Goanna area to the north. However its prospects of long term survival seem poor because the patch of bush it is in is likely to be much too small to sustain it and the Barton Highway separates that from the next nearest bit of bush.