What kind of evidence are you after?
I've given you the instructors names, the aircraft used, the Canberra Aviation website with all the information including addresses. I've told you that Gate 3 is not their office but simply a focal point where you're most likely to meet them. If you actually visit Gate 3 there are some notices up on the noticeboard from Canberra Aviation about getting a constant speed endorsement on the 172XP. If you head out there this Saturday Raveen is starting back at work full-time so you'll have a chance to meet him and shake his hand. If you head out there today or tomorrow Brian Candler will be working. Of course if the weather is bad there is a good chance they'll be either at home or working in the office.
The Canberra Aviation business name is registered to Goulburn Aviation Pty Ltd as i mentioned:
ABN Lookup - Current details for ABN: 25 105 401 036
There was an article when it first opened in Canberra in Australian Flying:
Canberra gets new flying school...at last
Canberra Aero Club links through to Canberra Aviation for flight training:
Canberra Aero-Club - Flight Training
They don't advertise for students because they're busy already and they cannot find any decent instructors to handle any increase in the workload. Besides people that want to learn (like me) generally seek out the local school.
What exactly would you like?