Paul - The clamp on my trigger was too big for the diameter of my pole so I had to put a sleeve (cut from plastic waste pipe) around the pole before attaching the clamp. By not tightening the clamp too tight, I am able to slide the whole assembly up and down the pole if I need to (if I need to grip the pole 2 feet from the bottom, I slide the whole assembly up 2 feet - it works great).
If your clamp is the correct size for the diameter of your pole, just try not tightening it too much and see if it will slide up and down.
Mike