Tight grip - that'd more likely be my guess too. As you raise the collective from the ground the governor is trying to close the throttle, but a tight grip will stop it from doing so, RPM goes up. Easily done.
I also know of an R44 syndicate in Denham with a spare space, Clipper II, Garmin 430, GPS, bladders, all the toys... 1/4 share, £175/hr+fuel. PM if you'd like more info
