I've had a Google in here, and from previous postings it would seem
impossible ?!

The kitchen cold tap coughs and spits, not always, but about a third of
the time it's used.
I also hear similar noises coming from the loft tank feed pipe where it
passes through the airing cupboard, but this is rare.

My water supply comes from the stop cock, through a water softener
(Kinetico dual salt block type) and directly into the cold tap at the
kitchen sink. Mains water pressure is very high (the garden hose will
often fly off the outside tap because of it (though not this year of
course) )

Any ideas ?