JimL,
IIRC, Lee hung on to the passenger by holding on to the external cable to for the cargo release! The co pilot made it to the dinghy, but Lee was in the water in shirt and slacks for about 30 minutes before being winched. As you said, modifications to all S61's after that, but also we finally got goon suits for the drivers
Only the week before, those of us in the Brent Field had been firmly told that immersion suits were not required, and to stop agitating. A week later we had a telex requiring sizes for all crew, issued within a month!
Re the medevac, rumour had it at the time that it was a quite minor injury, certainly not a broken limb.