problem with a tree in my garden

thanks for all the advice everyone.
wylie has by far the wisest advice, of which I'll probably play the fool and ignore. No offense wylie, he just really made me curious. Normally it is the path I'd follow. For instance the fence has also blown over with a different neighbor (bad things in 3's) and I've told him what every he wants to do, I'm up for it. I'll give him a hand digging and replacing like we did last time, or I'll go halves in a brand new colourbond if he likes... what ever, he's cival and we have a great relationship.

I rang my shire today and went the other way. I asked what I could do about a neighbors overhanging tree. At first the advice was simple. Feel free to trim away up to the boundary. However, when I said it was a large gum and the costs were considerable she put me on hold, only to return to say I should contact the citizens advice bureau.

So I rang them asking what I could do and again is still cloudy. They referred me to their Web site faq which I said Id read but was still confused. They said write the owner a letter detailing the damage and come to an agreement. If that fails and I suspect it's unsafe then get an arborist to come and get a safety audit and present that too the council and if needed a court.
She basically said it's a difficult path if you can't come to an agreement.

In the mean time, the shire has referred an email I sent asking if there was a preservation order to another department. Could be up to 5 working days for a response.