outofwhack,
Being a newbie - dare I ask the question why helicopter pilots dont have parachutes. The old reason of not being high enough to use them does not apply anymore. Base jumpers prove that.
Parachutes were worn in the Whirlwind 10 when going to higher altitudes, it was to do with the possibility of an aircraft fire and the low rate of descent in autorotation.
The Flight Reference Cards gave the abandonment drill to be followed (something along the lines of: Open windows, control frictions full on, disconnect mic/tel leads, undo harness, sit on window sill, facing inwards and roll out backwards from aircraft window).
There was a note at the bottom of that page which worried me quite a lot. It said
"Warning. Objects jettisoned from the aircraft in autorotation may go through the main rotor disc." 
As the pilot, I can't think of another phase of flight when I would want to jump out.....most of us said we would give the cyclic a kick to the left, to try to roll the aircraft way from us.