In the bathroom I have an Armitage Shanks Tiffany close-coupled WC with push
button flush. It is approx. 3 years old.

I have recently noticed that there is a very slight but constant trickle of
water into the bowl as if the siphon has not shut off completely. This is
not a case of the push button assembly pushing down on the siphon as the
flow does not stop when the lid is removed.

I have replaced old siphons in my time but this type is new to me. I don't
know whether there are any serviceable parts. Pictures at:

www.paperman.myby.co.uk/pics/Cist11.jpg

www.paperman.myby.co.uk/pics/Cist22.jpg

Can anyone advise me what the problem could be and let me know if it is
curable or will the whole assembly have to be replaced.

Thank you.

John