I feel this is a stupid question and that I've got a blind spot about the definitions .
I've got an alarming water hammer related to the WC flushing .It started after someone who described himself as a plumber took out a cylinder type thing from the tank and replaced it with the more traditional (IMV) globe ball float thing .He charged me £120 and said he could tighten up the external flush lever but he'd have to take the tank ( just wall hung ,not boxed in ) off the wall .
Anyway ,anxious to use a professional ,I messaged the man who installs and services my central heating .
He says he'll have a look and see if it's something he can help with .But maybe I've committed an error and asked the wrong tradesperson .
Please send help ,my brain is fried with the heat.