Where did you source the reaction bars from Dave?
Regarding the top bolt would it make any sense to strap the spring to the shock absorber before removing in some way. I am intrigued where the problem lies in restarting the thread I assume it becomes mis-aligned. It is on my list of things to do before the 'season'
I will post a photo of my 'spline cover' I picked up some aluminium vase inserts that are used for memorial stones that a nursery were selling off real cheap (50p) and I thought they will come in handy for something and they did they were made for the job!
Any darkly lit cemeteries nearby