I've no idea what a compliance plate is and what it would be doing on your driver's rear quarter panel. But thankfully there is this interweb thing.
http://www.rta.nsw.gov.au/registrati...s_nov_2007.pdf
From the above document:
"In certain cases, a vehicle without a compliance plate may be registered if the vehicle has been shown
by a letter of compliance to meet all applicable Australian Design Rules. A letter of compliance is a
statement from the manufacturer indicating that the vehicle complies with the Australian Design Rules
applicable at the time of the vehicles’ manufacture. A letter of compliance can only be issued by an
authorised representative of the manufacturer."