Hi - I bought and installed a Wirquin MW2 dual flush from B&Q
(http://www.wirquin.com/sitegb/accueilgb/indexgb.html). The problem is
I don't think its working correctly. If I press either the half or
full flush and let go it flushes about half the water in the cistern.
If I press and hold either button then it flushes the whole cistern.
The only difference I can see between the two buttons is that the full
flush lifts the plunger thing (that sits over the hole into the pan) a
little bit higher than the half. Does anyone else have any experience
of these and how they're supposed to work ?

TIA

Peter