No, I didn't, you're quite correct. Thought it was too obvious to mention, but my mistake. Could it be it just needs flushing out or is it possible for the standard +/- valve to break also?
I had two upstairs radiators go cold on me roughly around the same time as each other. The one in the spare room I\\\'ve fixed by freeing up the pin in the thermostatic valve that had stuck. I hoped this would then kick the bathroom one into life, but it hasn\\\'t. That one has a normal valve on...