Wow that's pretty poor. And very poor of park management, they should have offered to move you to another site. Many years ago up at Cairns we were camped next to a guy in a tent who had his radio plugged into the power box and would play his radio all night. When we asked him to turn it off he said he couldn't go to sleep unless it was on, he didn't seem to care that we couldn't go to sleep with it on. So during the night we would unplug it from the power box
Another time we pulled into a site after dark and after hours by pre arrangement, we had someone so far into our site we had to back in on the most unusual angle took us ages. Other's came to help but the guy next door stayed in his caravan and he even commandeered our firepit. We complained to management, who basically said they couldn't do too much about it now everyone was in their spot but did give us a bit of a refund. Maybe you should ask for that.
Not what you want, not nice to have some sort of confrontation with your neighbour because they are doing the wrong thing. And I wonder why we all want to free camp and not stay at caravan parks
Hope you still have a great time in the area, lots to see there