So this is the biggest issue with Kudox rads...Interesting What a catastrophic and life changing issue... http://www.diynot.com/diy/threads/kudox-radiators-never-again.475027/
Total BS... Never had a problem remove the plugs, but I do have purpose made tool to fit them properly (made from a piece of flat MS bar)& don't relie on a large screwdriver which usually has a tapered blade & seldom a good fit.
Bent 22mm here, folded into four corners. Doesn't take much to break the seal of the paint. If It struggles I use a utility knife around the plug and rad.