Thanks for the replies about the Emergency Lube System. I guess it was as a result of specific incidents in the 70's but just hadn't heard the details of the events.
Did have one of my own in the late 80's here in the Falklands (flying with David Mallock) - about 5 minutes after taking off from Mt Pleasant heading west, a brief sound of squealing metal followed by a loud bang, engine oversped and ran down, oil pouring down the outside, and inside in the cabin throught the shrapnel holes in the roof !! There was (sort of) suitable ground beneath us so we landed immediately.
The aircraft was recoverd to base the next day underneath a Chinook (just before the phone call from Head Office saying "under no circumstance undersling it - not covered by insurance" ......)
It was a high speed input bearing failure, never heard any subsequent suggestion as to why it had failed.