Brush Head,
yep the others are right. Fit a Torbeck valve.

I recently fitted one of those Coffin tanks from ScrewFix. Everything
was OK except the very noise BallCock valve they gave with it. It all
worked fine but it took such a long time to shut off the water. Due to
the cross sectional shape of the tank the rate of rise of the water is
very very slow so it took a long time and was very noisey.

Fit a TORBECK.

Chris.