Aser - yes that's him - he and another good friend survived, sadly some cadets who were on air experience did not.
Toolguy, thanks for that - it is as I suspected, the disconnect coupling needs to be well maintained - even using the wrong kind of grease can cause the spring loading to stick and prevent proper location of the drive teeth. The Wessex drive disconnected and the TR started to slow down, when the drive bit again the shock loading twisted the TR driveshaft like a coke-can and the video posted by aser was the end result.