Another Torbeck problem. Plumber replaced a like for like Torbeck valve which I had bought as I knew the shank length would be the same length as very short pipework so knew it should fit. Worked for a few days despite it dripping from the blue screw on cover to the diaphragm housing, then it would not shut off without some jiggling about with the float arm. Took it to bits, watched all the YouTube videos, put it all back, would not shut off at all. Nipped round to Screwfix for another, left the main inlet pipe in place and put the new one in after putting the high pressure bit in, mains fed supply. Still drips badly from blue screw bit but does shut off but with a loud squeak noise now which it didn't do before when it worked. I know these fill valves are not popular in some circles but anyone any ideas as to what could have caused the first one to not shut off?