I am on Go large plan and always have problem with streaming from tvnz. So i thought i could just download whole and watch it later. so I used script here to get url http://userscripts.org/scripts/show/25685
and download with downthemall and with in less than a minutes the download was finished.
So for anyone who have this problem give it a go..
I still don;t know what the diff but very happy.