Alan, sorry to here about your crazy neighbor light problem. There is an old IIS thread on the same subject here:
http://www.iceinspace.com.au/forum/s...ad.php?t=32222
That guy took out an AVO i believe.
A close row of advanced Leighton Green conifier trees will block off a boundary in a couple of years. If you rig up a wire strung between two poles either end of the boundary you can hang a sliding tarp on it. The poles need to be high enough to get the tarp up where it can effectively block. I say sliding tarp because if the wind comes up you want to be able to tie it off on one pole. Another option might be a full blocking shade sail under tension, but that it going to cost some money for steel posts in concrete and the tensioning fittings.
If your willing to do a Houghy and move house, there are still dark areas around Lake Macquarie.
Good luck.