Yeah sorry guys, automet= Auto METAR (on the hour and half hour). Someone I fly with rang BoM and asked if the AWIS and AUTO METARS are derived from the same equipment. The answer was that yes they were, the decision to have an AWIS on a frequency or phone number was the airports decision. Cannot vouch for the veracity of info, just what I was told.
So for clarification, AWIS is fine for actual terminal QNH minimas (updates every transmission cycle), provided obtained in 15 minutes etc.
AUTO METARS cannot be used for actual QNH, just forecast terminal QNH minima (due to the fact that they are only 'snapshots' of the weather every 30 mins).