Welcome...I'm sorry to report I have no experience with Enerpac oils. My research did not reveal anything particularly special about them. The HF series is an ISO 32 so using an ISO 68 would be to heavy. I don't know about consumer protection laws in Australia either. However, it has been my experience as long as you use an oil that at least meets the specifications laid out by the OEM, you should be fine. In this case Enerpac points out several times, a high viscosity index is required. I'm sure deeper research would reveal more. My recommendation would be Schaeffer's 254 ISO 32 if your using the HF series or Schaeffer's 275S ISO 32 if your using the TH LX series. The 275S could be used to replace both. My e-mail is
www.schaefferoiltexas@gmail.com if you have additional questions.