I have a problem with a noisy float valve in our high level cistern.

The cistern fills very quickly and efficiently but as it shuts off there is severe vibration noise coming from the float valve. I know we live in a high pressure area (5 bar) so turned down the isolating value but the problem persists.

Should I turn down the internal stop cock or is there another remedy?. I don't really want the performance of the shower and other fittings to suffer.

Thanks

The installation is new so it sounds like additional clipping is required