I think I see what the problem is, though it will only be helpful later.
The rover blade disk has the central bolt, and should have 3 small bolts that also connect to the boss around the central bolt like a triangle. Some retard has put the disk on, and not put the surrounding smaller bolts on, so the thing just spun like a top and has slowly sheared its central hole out. If I can source the correct three smaller bolts and washers, I may not need to undo the central bolt at all (for now). This would of course simplify taking the disk off, as you would take the central bolt out first, and the other three later without the boss spinning issue.
If a rover owner can verify the above setup, I will start looking for another dead rover and see if the blade disk has the bolts in question.
I will still see if I can get it off with a rattle gun, but this might be a cheaper way of doing things.
