I made my own headliners with some panel board, the kind that door panel is made from, some vynal & high temperature velcro to stick it on.Here are a couple of pics,it was easy to do & cost less than half of what they sell for
this is the glue if it's available in AU, I am not sure
They have reduced the temperature by about 70 % & never moved since the day I put them in.The velcro is 1" wide. PM me if I can help you with it at all.