I’m in the process of changing the cartridge on my Hans Grohe kitchen tap (pull out hose type). I’ve managed to remove the remove the handle, but can’t get the deco ring. The written instructions and demonstrations on YouTube videos show it simply popping off with a flathead screwdriver (as pictured in the attached image) but mine is not budging. Could it be limescale? I don’t want to force it as it seems like it’s plastic and therefore easily breakable. Any suggestions would be most appreciated. Shirley