Do my clients travelling via Guangzhou to London 06 July 2013 need a transit visa?

My clients are flying with China Southern Airlines to London vai Guangzhou they are in transit at the airport for 8 hrs 30 mins but are taking Southern's option of a day room in the hotel immediately outside the airport. I have conflicting information on if they require a transit G or not. I have been told they simply need to fill out an "Application for Stay Permit" then I have been told they need a transit G and according to this information now, They would fall under the 72hr free rule? Both are Australian passport holders. Please help!