Thanks Guys,
I have tried a cable snips which has worked very well since it can grip the valve head very easily. Since it is hardened steel it can cut into the brass and thereby give a better grip. However one valve still won't move so its a plan B - if I can find one.
Any ideas....
I was recently trying to bleed some rads around the house and discovered that a number - luckely small - of the valve needle heads were badly worn and wont open with a standard valve key.
Does anyone have a suggestion as to how best to open these valves - tips, techniques or tools would be...