I agree. Brute strength and a pair of pliers would take the screw off. New colour kits down use that type of screw, they use a philips screw and screw it directly into the plastic. I know because one of screws wont tighten, just spins around
I had the same thing with mine on one I have metal then on the other it's just plastic poor move by DYE IMO!
if you are really stuck i have a spare colour top, its got a broken lid so you'd need to swap your lid in. either way if your stuck and need to resort to just breaking it off i can send you a replacement for a few quid.