Lamona, LAM8301 Slimline Dishwasher never stops

I have a Lamona, LAM8301. On refitting the U bend under the sink I forgot to remove the drain plug from the attachment for the dishwasher. The dishwasher was running for a couple of hours unable to drain water. I eventually figured it out, removed the plug and the dishwasher drained but now it seems to never stop trying to drain. It always comes back on trying to empty the water and does not start a new programme. The thing just hums away. I poured more water into it and it does pump it out like it is supposed to but it never stops.