I can't see CASA allowing Chuck and Larry to pull up in the Ford F250 drop the tail gate and do the 100 hourly on the C310, Tiger moth or Lear 60 issue the maintenance release with their FAA Airframe and Powerplant generic license then drive away ? This what happens in USA with about 150,000 part 91 private aircraft each year nothing more nothing less.
4 Holer is there any other way to interpret "FAA Maint for GA"?
...On the other hand, Carmody and Walker tells us that "you don't need an AOC to run a flying school any more". (...but you do need a Part 141 Certificate with a 2" thick manual)