Hi Oenpelli-Girl,
I'm not sure if keeping your childrens outside is the best idea, because you won't be able to regulate the temperature (remember excessive heat will kill a snake before cold will). Also, unless the enclosure is perfectly secure, there's also a risk of some other critter knocking the enclosure about and then maybe eating or killing your snake. Wild reptiles, and maybe other animals too, may also pass diseases on to your snake.
Even tho childrens may occur naturally where you are, they aren't confined to an enclosure, so can seek sun, shade, warmth and anything else they need when they are in the wild. When they are in captivity, they lose the ability to move around to help to maintain their body temperature.
Also, I'm not sure about night time temps where you are, but my
childreni have 24 hour heat with a 31 degree hot spot, so unless you can guarantee that your snake will have those kind of temps, then your snake could have issues with digestion, which can lead regurgitation or the rodent rotting in your snakes gut, which can cause even more problems.
If you can post some pictures of where you plan to put your snake, maybe someone with a bit more knowledge on keeping childrens outside can have some input.
Sorry, can't help you out with the NT permit specifically, but keeping good records will mean that you won't get fined, will minimise any chance of your animals being seized, and it also means that you know what you've got and where it came from if you ever want to breed.
Good luck and I hope you and Bindi are very happy together!!!
I think that Bindi is a perfectly good name
Bindi is my little mac's name. I named her that cos she had a little red spot on her head, which has faded as she has grown
lease be advised that the wildlife mustbe obtained lawfully (i get that) please attach copies of your proof of 
