Fences – Common Property

Hi

I live in a large town house complex whereby my garden backs on to 3 neighbours within the complex and one who owns a house outside the complex. 

The fences have been replaced as 'work in progress' and 2 years ago part of the fencing on my lot was replaced.  The only part of the fence not replaced is along the boundary between my garden and the private house garden.  The fence divides my townhouse and 3 others.  The new fence is color bond and the existing fence is timber.

One neighbour decided to add a colour bond lattice on top of the fence that divides her property from mine however due to the size of my land the lattice covers only one third of the fence from my side.

She got 'approval' to do this by having a 'general' conversation with the secretary of the EC.  The addition was done without my knowledge.  I contacted OFT who advised it contravened By Law 17 and also 62a of Strata Management Act.  I complained to the EC and they decided to 'approve' the lattice since the owner had already paid for it.  I am still objecting since this lattice only covers one small part of the fence from my side and I do not want to extend this since this would impact not only on the other two neighbours in the complex but the neighbour in the private house. 

I hope this makes sense but what right does the owner of this townhouse have to make an addition without proper approval and without discussion with the neighbours who adjoin her property?  Also, can the EA just 'approve' this retrospectively because she has already paid for it?

Cheers