The little bit I have found on internet all suggest by Vic law the registered owner is not always the legal owner, that the registered owner is the custodian as such for vic roads, fines etc, the actual legal owner is the person who can prove ownership.
I have a receipt of sale from the previous owner in my name signed by him, I have loan contracts to purchase the car, in my name, I have bank statements in my name with the monthly payments.
She has nothing apart from saying I gave it to her, in part correct, whilst we were together she had the car at her disposal, if in the event we separated which we did only months after I purchased the car, she was either to pay me the money for the car or return it to me, but didn't happen she refuses to give it back and placed an AVO on me.