Doc,
This may sound silly, but have you loosened the top clamp pinch bolt ? Of course you have how silly of me to suggest otherwise.
Have you tried to apply pressure to the cap by collapsing the forks, maybe slide the forks up through the clamps until about 50mm of top exposed, then re clamp the forks, pull down with tie downs and gently tap area around cap.....and ditto about the safety glasses.