I’m not very knowledgeable in legal proceedings but I did manage to find this online. It gives an overview of age of consent laws:
Age of consent laws
I don’t know what the law regarding age of consent was c. 1982 but I do know anyone who is now in a ‘supervisory role’, such as a teacher, etc, is guilty of an offence if they sexually engage with a child of up to 16 and 17 years of age under their special care:
Sexual interactions with 16 and 17 year olds under special care
Although the legal age of consent throughout Australia is either 16 or 17 years of age, legislation in New South Wales, Victoria, Western Australia, South Australia and the Northern Territory makes it an offence for a person in a supervisory role to sexually engage with a person under their special care who is aged 16 or 17 years. A person in a supervisory role providing "special care" may include: a teacher, foster parent, religious official or spiritual leader, a medical practitioner, an employer of the child or a custodial official. For further information regarding sexual interaction with 16 and 17 years old under special care please see the relevant state or territory legislation.
I presume the above includes a Physical Education teacher at the same school as the student.
You would think Chris would be able to be charged irt those offences. Although, at the time, maybe there either wasn’t a complaint made and/or the age of consent laws in NSW were somewhat more ‘lenient’.