Huge tree with massive burnt out hollow section at base of trunk, big enough for a person to easily stand in. Unable to get photos of buds or fruit but hoping these photos provide enough for identification.
Thanks for that info. I did look for buds and fruit on the ground, but like you say I was reticent to link any to this particular tree because there were others nearby, but mostly only Spotted Gums. There was another smaller tree nearby that did have scribbles on the smooth bark, so like you, I am reasonably confident that they are Blackbutts.