Any solutions? Problem - close-coupled WC button push flush plunger is de-railing and jamming due to worn bottom washer. Solution would be to simply replace the unit. However the bottom outlet is not standard 2" or 1 1/2" but 2 1/2". Have searched all trade outlets without success. They simply don't exist. Have I got the only 2 1/2" outlet flush assembly in the world? Alternative solutions - to replace cistern with standard fitting and thereby risk leaky misalignment with old WC pan! Or replace entire WC and risk realignment with tiled floor! Really stuck on this one. Anyone been there and lived to tell the tale?