I have no helpful advice hun...other than- have you tried those 'baby sleep positioners'. I used one with Florence in the UK when she went from her basinette to the cot. She was great with it and it helped her feel supported and cosy. She eventually grew out of that too only because she was moving around so much. They are great as they are not restrictive to baby size.
Good Luck hun. Hope that helps in some way. xoxoxo
Just google 'baby sleep positioner' in images to give you an idea of what I mean if you haven't heard of it. They sell them in Aus too. xoxo