Scampi,
Just look at what the user ID is on the old ipad and put it into the new one, then delete OzRunways from the old one.
If it gives you an error when try to move to the new iPad*, send us a support email via the website and we'll transfer it for you.
Cheers,
Bas.
* Because we don't let people do this too often for obvious reasons. But it happens someone buys a subscription on a friend/family member's iPad, then decides to buy a new iPad a few weeks later...