Thanks Oilman. So, it's the plug marked "P". I've read other posts on the forum that have suggested that P is for the pressure - don't touch it. I was at a loss after that!
Stupidly let the oil tank run down. Refilled, but now the boiler won't fire up, keeps going into Lockout. I've been told the air needs bleeding from the oil supply line.
How do I do this?
