With regard to the supply of 12g CO2 cartridges. I think that looking at these 2 links you will find they are the same item from the same manufacturer.
http://finewhip.cart.net.au/store/12g-un-threaded-keg-chargers-x-1.html
and
http://www.ezychargers.com.au/product_info.php?products_id=479...
