Hi, I have a noisy cistern that appears to be leaking into the pan a little but also making a very frustrating water noise from inside, I have attached a picture of the offending item that is dripping water constantly. Guessing the whole lot needs replacing but not sure what to ask for when getting a new one. I should be able to replace it ok as it just looks like turn the mains off then unscrew the main water pipe which goes through the bottom of the cistern and into the offending part. Can anyone let me know what the whole unit is called and also why is it leaking from what looks like a pipe? Thanks