When i rang Jayco Geelong about buying 1 front fly to suit my can they said they had 1 "set" to suit a front&rear expanda van in stock, would not split for me at the time. So they may still have them, this is over a week ago though.
Holiday annexes, got one from there and its great. They sent it out and I fitted it in about an hour $570 very well made. Has made a huge difference to the temperature in the van not to mention pitch black in bed when the sun comes up. www.holidayannexes.com.au