I understand that Aitsl wants 4 years of university level education, is it possible to apply with say a 3 year B.Ed, followed by a level 6 OTHM diploma ?
This may be alright as long as you can demonstrate that the Level 6 diploma is a university level qualification. It should have been taught and issued by a university level institution. It might be useful to get some kind of written confirmation of this from the university.