Just moved to a converted victorian flat.. :-S
During the night I wake to the sound of really loud running gurgly water coming from the water tank, which unfortunately is just above my room. The noise is traced back to the toilet, though nothing obvious seems wrong when flushing. The cistern is covered up with tiles, so can't be opened without causing damage.
Does anyone know what the problem is or how the noise can temporarily be stopped? Tried flushing the toilet and noise remains. Strangely it seems to go away during the day...