Bristol Sycamore

When I was a teenager in the early 1950s I used to go to watch the St Austell Gulls motorcycle speedway team at the stadium on Par Moor.
One evening there was a half-time demonstration by an RAF Sycamore helicopter and just as the loudspeaker commentator described how if the engine failed a helicopter would just autorotate and land safely something went wrong and it dropped out of its hover at around 150ft(?) and crashed heavily. As I remember it either the main rotor or the tail rotor ended up in the crowd of spectators.
Can anyone tell me the final outcome of this crash as my memory is that one member of the public lost an arm but I remember nothing of the crew?