Do Australian citizen family need G Visa in advance, to stay 47 hours in Shanghai?

WE are family of 4 with dual UK/ Aust citizenship ( separate 4 passports)returning to Australia in October . We want to extend our trip to fly KL to Shanghai on China Air for 47 hours sightseeing then fly Qantas to Sydney( our home). Transit visa also seems to be very expensive if we apply in London so we cannot do trip if visa will costs £140 each.
Are we visa-free because one of 30 countries listed on your site?

If not, can we get issued a Transit G visa on arrival in Shanghai, if we produce onward tickets and photos and completed forms V2011A x 4 and Supplementary V2011B as applying outside Australia. etc at Shanghai airport . What will be the cost of GVisa in Shanghai? Thankyou