Are they all a standard fitting? i.e. if i can't find an exact replacement will any flush valve do the job?
yes any one will do
But if the syphon is blue plastic you just pull a pin out to remove it and simply pop a new one on
I'll take a photo. Stupid thing's sticking and just trickling water all the time
That happens here with just a little lime scale build up on the pin and diaphragm.
Having taken the valve out it appears the lever that lifts the valve has [i]slightly[/i] chipped, and it's such a delicate design that as a result, it now misses the guide and so gets stuck at the bottom of it's action.
New valve needed i think.
No major problem though - luckily the valve from the downstairs loo fits and is working so we're ok.
Thanks for your help chaps.