John Picton wrote:
OK I realise this is probably very basic....

When I flush the loo, the cistern makes a noise for a few seconds just
as the cistern finishes filling. The noise is like a mini foghorn. If I
turn on another cold tap in the house the noise goes away while the tap
is on.

I am guessing that the ballcock / valve my need replacing but is there
another wayI can fix this?

TIA

Thanks for all of the suggestions. It looks like I have a number of
things to try (keeps me off the streets....).

I really appriciate the help ... first thing to try, I think, is
replacing the washer, it looks to be the most simple solution.

Cheers

John