hatch at bottom right on front flaps down to reveal a big round plug and a wee plugged hose on the left which you can pull out. Get a thin tray eg baking tray to catch water and gently unscrew the big plug to release waste. Watch out it doesn't all flood out. Once the exess water is cleared take it right off and pull out any debris. That might be it but for good measure pull out the wee hose from the left, unplug it and drain it. You can blow through it to try to dislodge other debris from the filter once the water is out. If it still does not run as normal then I am afraid I am out of ideas ... that is the stge ours is at now. HTH
Calum
October 2008