Ok, back then the infringement system was not yet operating, so your matter went to Court... and from what you have explained you plead guilty and do have a criminal record related to the stealing charge. I am assuming that the goods were not of much value... so it would be considered petty theft, and that was why a fine was imposed, which you promptly paid.
Past and present criminal conduct
Criminal conduct refers to conduct punishable by law and has been actually punished by a conviction for an offence.
Factors which are relevant in considering your past and present criminal conduct include:
• the nature, severity and frequency of the offence/s
• the period since the offence/s were committed
• your record since the offence/s were committed including any evidence of recidivism or continuing association with criminals and any pattern of similar offences or blatant disregard or contempt for the law
• any circumstances surrounding the offending which may explain the conduct such as may be evidence from judges’ comments, parole reports and similar documents, and
• any good acts after the criminal conduct that are indications that you may be reformed.
Again, it is not ideal that this record is on your file... but if it is an isolated incident... it is not major or serious crime, so theoretically, you should still pass the "character" test.
Please accept and rate my response, cheers, James