There have been vehicles sold at the auctions without any Compliance Plates, and these have been succesfully (and legitimately) registered when accompanied with a Manufacturer's Letter that states that the vehicle, when built, complied with the Motor Vehicle Standards Act 1989. (My 6x6 is one example).
Having lost your Compliance Plate, I would contact Jaguar Land Rover Australia and inquire how to obtain such a letter. The Good People at Australian Frontline Machinery should be able to assist with who to contact.
Ensure that any receipt or blue slip shows the correct chassis VIN, and not the erroneous number on any other plate.