I am having the same continuous problem with my Roca Toilets. I have tried un-screwing the screw slightly which is located underneith the two Buttons , this also worked for a day or so but the toilet has since returned to its continuous flushing state. I have also cleaned the Rubber washer (located at bottom of systern) I have been tempted many of times to get a Hammer to the toilet systern (this would not solve the problem obviously but the satisfaction of revenge would be sweet if only for a brief moment). The only way to stop this flushing problem I have found is to press the Large flush button once, wait for the systern to re-fill then press the small Flush button and wait for the systern to re-fill, The small flush may need to be pressed upto 3 times to stop the toilet from flushing (this stops the problem on my toilets 90% of the time)
After thinking about the comments posted above and examining the system I have, it appears that the componants are really cheaply made plastic, there is a possibility that a couple of moving parts are binding together on the flashing (the little stub/tit that is usually found on Plastic moulded componants. These Stubs/tits should be removed prior to assembly) this could be the reason for the system not returning to its origional position.
Do Roca Sell a simple single flush alternative that can be installed instead ?
Chris
January 2009