Hi, I have a WC cistern with a Flush Valve in it that is allowing water to dribble through and in to the pan. I guess the black washer needs replacing or something else if there are any ideas? But, the marking on the valve is 'Pacific', the company who made these is Macdee, who have told me they stopped production 2 years ago and there are no spares! I have looked around, and there are no spares. What do you reccommend? (Are there any spares, should the Flush Valve be replaced, what is a good flush valve with a Top Button?) Ta ta ta.