Try
Formula Offroad Sydney...They make a rear wheel carrier that mounts on the tow bar rails up and under the bumper...Their Web site doesn't specifically say Jeep but they do make one and several contacts and a mate who have them on their WH. By the looks of it. it wouldn't be too hard to alter to fit the WK2 if not a direct fit. Formula Offroad may already done so....As far as I know diesel is ok to carry on the rear bar.....Petrol not so.