Old radiator bleed valve
Hi all, looking for some advice if you're able to help. I bleed my rads about once a year but there is a radiator I've got that I've not been able to find the bleed valve....until now.
I saw people saying that it might be on the top at the back so I ran my hand along the back and sure enough I found it. I've tried using my radiator key on it but it doesn't fit on.
This valve seems to be circular whereas my radiator bleed key is the more conventional squared off slot.
Am I going mad or is this valve circular and if so is there a word for the key I'm supposed to use because thus far I've not been able to find it online.
Thanks