For no apparent reason my waterfall tap has started to leak. Water is coming out of the bottom of the pillar but I've checked the hot and cold connections and they're both fine. I've had the cartridge out and that looked ok too so I checked the seating and put the whole thing back together, double tightened everything, turned on and the leak is worse! It only leaks when the tap is turned on, applies equally to the hot and cold so I'm at a complete loss. Does anyone out there have any ideas?