My roca toilet has a leak underneath the tank, it seems to have left limescale from the water, around the washers of the fixing bolts, further more more the cisterns seems to re-regulate itself all the time, and there is water trickling in to the bowl, which i asumme is the overflow system working properly. How do I fix this, will i need to replace the bolts and the rubber rings? and how do I removed the top (crescent moon + round flush mechanism/two flush)?

Ben law, October 2008

It could be that the main flush screw wasn't tightened down on installation, allowing the unit to leak into the sealed area. To remove the top, depress one of the flush buttons and carefully lever out the other button with a screwdriver, remove the initial button and you will see the attachment screw. Undo this to remove the top. Ensure the bezel is lined up with the slots to reinstall afterwards.

Simon Jeffery, December 2008