You should be able to log into www.skygo.co.nz with your account details, and watch online without needing to use an app. You may need to play with flash settings, if you use Chrome. The picture is scaleable to full screen.
Help is at https://skytv.custhelp.com/app/answers/detail/a_id/2445
As far as I know, this doesn't count as one of your three MySky devices.
Major