Answer
Its under the bike (almost!) between rear tyre and crankcase. remove left side panel to disconnect starter solenoid and battery ground lead. in front of rear tyre you should see a 10mm head bolt. undo both sides and a trapdoor opens. you need to put a piece of 4x2 or similar under rear tyre to get clearance to get completely open and remove battery. fyi, the bike was designed in america for the american market