I have received a full and very detailed explanation of what goes on at the rear of the 777 and its various systems from a senior engineering manager at Air NZ (NOT a Customer Relations person!)
He confirms that the fault appears to be in a failure in the Lateral Gust Suppression System. Such failures do not directly affect airworthiness and the system is not on the MEL.
He also says that NZ aircrew are incorrect in saying "they all do that" as aircraft are not regularly despatched with such problems existing.
A full and detailed reply from the right person at AirNZ - well done!