Apologies in advance for what will probably turn out to be a stupid question, but today I called British Gas as we had a radiator with a leaking valve which wou k d not stop. The chap came and drained the system down and fitted a nice new one as per the picture. All good then I just went to see how far open he had turned it open but have found that I can't turn it - either to open or close it - it has a screw in the top which I have taken out to see if that makes a difference but it doesn't. Am I missing something here? Also there is like a plastic ring part of the cover that is separate to the main cover which is loose underneath - is that normal? Thanks in advance for any advice.
. I would guess it is just tight, anyway they fitted it so get them back to sort it out 
