I used this stuff: http://www.acoustica.com.au/vybar.html
It came from SoPac marine in Albany.
I liked it because apart from being much lighter (the 48F type) it claims to not absorb moisture or disintegrate into millions of little bits like the stuff I was replacing.
Their little test / demo sound box thing is pretty impressive too.
I found them very helpful, however I was a little to enthusiastic and brought two sheets when I only needed one.
I will create a classified for the other unused sheet in case it is of use.