Engineer was delayed but I was informed so it was not an issue. The problem was a tun dish that allowed drips to escape and wet the floor. The engineer did not look at this but stated that he could see that the problem was the expansion tank bladder had blown so a new cylinder was needed. he said the problem was caused by not being serviced properly by completely draining the tank. He was to quote me for new cylinder and installation. I was not convinced by this as the cylinder does not have an expansion tank nor bladder and the dent he referred to was a slightly damaged outer case, This is not under any pressure and is thin sheet steel. Heatrea Sadia inform me that my cylinder is under warranty still and that my possible problem is an inferior tun dish, weak relief valve on the cold water side. They have offered to arrange an inspection of the cylinder should I wish it. Your engineer left us on good terms, he was pleasant and seemed on face value to be a nice person. I was not impress by his diagnosis and will not be ordering a new cylinder nor using Plumbing force again. Sorry.