Thanks for that I believe I have done it. They felt so tight I thought they were already fully off, but a good swing on it loosened them up. Probably 30+ years untouched so they might've stiffened up.
Long time lurker first time poster here, so Hi, your scribings have been of much use over the years so thanks to begin with.
Now to a problem of my own. I've removed and replaced radiators before, but it's the first time I've encountered valves like this...
As you can see they're very old...