Hi, just a little information please. British Gas came today to do some work and left the loft space open, so i went up to close it and noticed that he had messed about with the little expansion tank , and I noticed that there isn't much water in there ( below the ball valve) and also that there isn't anything covering it - ie no lid or anything - just abit of insulation around it. Can someone tell me if that sounds like a normal tank or do I have to call back British Gas to put it right. Thanks.