Anti Fatigue EVA Mat (6mm thick)
I have not tried this mat, but it looks like the closest thing to the mat I used for the Dive Helmet and the Viking Helmet available in the U.S.A. Comes in a nice 4 x 8 foot sheet.
This is a great product that I love to use. You can buy it here.
Stansport Pack-Lite Pad72x19x3/8 inch (Amazon Affiliate Link)
I have never actually used this one but it seems to be the closest thing I can find to what I have been using in Australia. and it's under $10