Mike ,I had a similar problem with my boot not staying open and upon inspection found the left spring was in back to front and the mechanism had some how flipped through, causing it to work against the other spring and drag the boot shut.It took a bit of time to work it out hense the "NASCO Boot stick".Anyway what I did was make a special tool for the springs using the diagram from the Workshop Manual. With a screw driver and a cover (rag) over the spring (to keep it from doing me any damage)and to keep it within the boot worked it and the mechanism off,turned it the right way round and using the "Special Tool" fixed it back into place. I also found it easier to do with the boot closed partially as there is less tension on the spring and a piece of cloth over the boot lock to prevent being locked in.It took me about 20 mins to do but the end result is the boot stays up unassisted.
Cheers Rusty (And good luck)