AS I was a rigger, who did the Vulcan course at Waddo in 73, and, on posting to Akronelli, was ultimately employed on the Lightnings of 56 Sqn. We must have been there at the same time. Now, I do have some memory of being told of the incident you refer to. I understand it happened at Waddington, as I say, this was second hand info, but here goes. My understanding is that the braking parachute door was as you say, wound down to its closed position, against the door springs into its closed position where the latches were set. The tool used was basically a screw thread (of some substance) with a hook at the bottom which located on an aircraft mounted bar, the other end had a handwheel, which was used to screw down the door. There was little mechanical advantage with this tool, and, as the door neared its closed position, was extremely heavy going. The practice of sitting on the door was a way of taking spring force out of the work the handwheel was doing, unfortunately, on this occasion the tool slipped from one of its locating point, with the operator sat astride the door. ISTR being told on the course at Waddo, that the tradesman was thrown forwards into the trailing edge of the Rudder, causing severe head injuries, he the fell to one side and down to the ground, accusing further injury. Not a nice way to go I should think. Suffice to say that the story was passed to "riggers" on the course in the hope it would make them think before they bent any rules about operating the equipment. I can't help with any alternate methods of closing the brake para door as I was never ultimately employed on the Vulcan. Hope that helps, who knows, it may jog even more old riggers memories !!
Smudge