Most / Many / Some (not sure which!) councils have a "compliance officer" who is responsible for ensuring that by-laws are respected. They are often university trained and energetic in their pursuit of boundaries crossed, regardless of the whether works have been commissioned by council, residents or companies. Only takes a phone call to the main number. Your local council will be listed at
Whitepages or you can find them at yourlocalityname.yourstate.gov.au
If you don't have a compliance officer, ask for the ranger.... cue dark chords of doom...
Last resort, call one of your local elected representatives. Local government has the highest number of reps per head of population and through much of our wide brown land has yet to be thoroughly tainted by the party system. Your councillors are usually genuinely interested in hearing from you. The council website should list their email address and phone number. Failing that, rock up early to the next council meeting and say you want to speak, they'll give you 3 minutes before the meeting proper starts. Council meeting dates and times should also be listed on the website.
Easy as pie

BTW the fence is still there as of today! really is ridiculous given the space they have