Today I broke the safety catch thingy on my Manfrotto tripod head....the little nipple that holds back the spring actually broke off the head, so the safety catch isn't sprung now. I want to check out new ones in Dublin tomorrow, but I'd like to take my old head with me (not the tripod though) for comparison. Not being too technical, I've tried every which way to separate the head from the tripod, short of a hacksaw, and I can't figure it out. Any ideas? Thanks in advance.