No comment on this accident as we don't know the facts until AIB has reported.
Done loads of spinning in the firefly (and other types) and recovery never a problem so long as the correct recovery procedure is followed and the aircraft is within CG and weight limits and fuel is balanced.
"Move the control column (centrally) forward until the rotation ceases".
If you only move the control column to a central position the a/c will go high rotational but if you then continue with forward column movement (if necessary to the forward stop) the aircraft will always recover.
The rate of rotation increases due to conservation of angular momentum - as the a/c starts to spin in a smaller radius the rotation rate increases to maintain momentum. Assuming you are following the correct recovery procedure this is an indication that the a/c is in the process of recovering.