May I refer you to their
funding page which says that you will pay over £65,000 ($91,400) within 16 weeks of enrolling, that is within 3 and a half months of pitching up there. At that point you are very unlikely to have completed your PPL, which costs about $7500, so you have overpaid them at least $84,000, and more to pay next month. From that point on you are entirely at the mercy of the ATO, they own you, and if they went bust you would never get it back. You can expect to have to keep some money in credit at a reputable flight school, but ony $1000 dollars or so. Great marketing, though.
Just think about the numbers. Say 20 students each with $60,000 overpaid against what they have flown (lets be conservative), that's $1.2 million of cash flow. Even if you (the ATO) had nothing in the bank before your course started you are now flush with yankee dollars. What will you spent it on? 40 students... 60 students...