The cache is not located at the published coordinates. It is the start of The Link to Shepherd's Lookout Walk instead.
This is the bonus cache for the Adventure Lab, The Link to Shepherd's Lookout Walk. You need to complete this adventure lab in order to get the information necessary to solve the final coordinates for this bonus cache.
The D/T represents that of the adventure lab since it is a pre-requisite. The bonus cache itself is a 1.5/1.5 DT.
To find GZ:
S35° 14.ABC E148° 58.DEF
Where A, B, C, D, E and F are all provided by the adventure lab.
I hope you enjoyed the bushwalk!