We had a customer in the same situation. He made an appointment at an Education visa school. He explained he needed the 3 months to prepare his education visa and they accepted his story. His plan was to not apply for the ed visa but do the dtv with us instead. But he actually signed up for the ed visa anyway and trains with us as a normal student.
Im considering launching a DTV plus course.the idea is its a cheap 1 year course with a letter and a link to a database that the Immigration officer can check. Its a bit premature as of yet but if it becomes a thing where Immigration want ongoing documents it will help. Some won't be interested but some of my customers want peace of mind but dont want to lay out for another full course. I have had 3 or 4 customers purchase new courses " just in case" and I advised them its not really necessary as of now. Let's see how it develops