Welcome to the JOF Dave! We were fortunate to visit your beautiful country last year. Although we didn't camp, our friends there have a new rv so more than likely we will get camp 'Down Unda' on our next visit. Not very often do we have Jayco owners from Australia here at JOF. Occasionally, you may have questions concerns about your specific tt that members here may may not be familiar with and may not be able to answer.
Was it a Jayco dealer you contacted, or did you call Jayco in Australia directly? Here is the
website contact for the Australian main office for Jayco. They might be able to also direct you to a local tow expert to help you with the tow set-up.
Hope you can get the set-up complete and be on the road soon enjoying your new Heritage! Congrats