One of our loos wouldn't stop filling last week and was overflowing on to the floor through the handle hole. The cistern is rather narrow and the plumber had to fiddle around adapting the replacement valve to fit the space. I wondered if he had bought the wrong one. This morning we received a bill for what seems an astronomic amount; won't tell you yet how much. What is a reasonable sum for this job? He tried replacing the plastic disc thing (torvic valve?) but that didn't work so was supposed to have tightened the nut so it wouldn't go on filling and would come back next day to fit a new ball valve; we have another loo so that was OK. We had to go out for an appointment and when we returned the bathroom was flooded so he hadn't turned it off after all. I improvised a series of bowls to catch the drips overnight. We turned off the stopcock downstairs but that only stops water getting into the tank and we couldn't go up to the loft to see if there was a valve to stop water leaving the tank. He didn't bother to do that either; just turned on the bathtaps till the tank was empty. Big water bill coming up no doubt.