Malabo - caution...
Malabo said: "............. To finish off the exercise we used to let it spin a couple of times and then chop the throttle and auto to the ground without ever moving the pedal off the stop, but you needed some altitude to get it to work out"
Maybe that proceedure should be checked.... ? Putting the lever down ia enough to stop the spin and enter autorotation - closing the throttle is a bit brutal and jeorardises RRPM . I guess you were thinking in terms of closing the throttle and lowering the lever shortly thereafter - but there is a huge danger - which I have seen often - that the throttle gets closed to eliminate the torque but the RRPM is left to decay - leading to a very heavy landing (maybe a hint of that in this accident) . !Caution!