Am I fine with the concept of a falling leaf manoeuver in training?
In an aerobatic aeroplane, for a post-PPL advanced student learning about the corners of the envelope, absolutely fine. We did it on my ETPS course - from memory in a Tucano, and probably the Hawk.
For a PPL student, in a non-aerobatic aeroplane, who needs to build up behaviour patterns that will lead to immediate stall recovery with low height loss. Absolutely not.
Pace>> I am not against taking an aeroplane to a full stall, and believe that students should be taught to recognise the stall, and recovery from it promptly. I am against holding an aeroplane in the stall once it clearly has done - that is either aerobatics or test flying, and is not sensible or useful flight instruction.
G