If you are ever on Garda, you should contact Andrea from Seatex boards, he changes the boom grip for you in no time. And if you want the original one from NP, just let him know in advance so he can have it home for your boom.
http://www.seatexboards.com/2010/index.php?option=com_content&view=article&id=63&Itemid=1&lang=en he does a good job and is even official NP re-gripper
Thanks Dennis...