airbrake, you ask if schools have MELs and if not why not.
Firstly MELs are only required for charter.
Secondly, the cost of setting up an MEL is prohibitive by the time you have paid to get it done, or taken the time to do it yourself; and then paid for CASA to approve it.
So most of us make do with the POH and CAO 20.18, and if we have charter aircraft, make sure everything works!