Actually, the user manual tells you this:
"In case of using Wall or Ceiling Mounting unit, by contacting your local dealer, ask the specified installation specialist to set up. Never attempt to install it by yourself. It could cause injuries or damages."

Most modern TV manufacturers list their TV as being "VESA compliant" and give a specific measurement like "VESA 75" - meaning mounts are a square at 75 x 75mm.

Looking at your manual and back of the TV in depth, I believe there are mounting holes that are VESA compliant, but as Hitachi did not want you wall mounting this by yourself, they declined to give you enough information.

Because we don't know which VESA mount system this TV has, I'd recommend a general generic mount, like this one at Amazon. Any mount of this "style" designed for a TV of 32" or larger should work just fine.

AMAZON

I'm not in Australia, so I don't know the local vendors, but an online vendor that serves your county and has this style of mount can be found
HERE.

Let me know if this helps..