My Electrolux Dishwasher won't fully drain the water, please help!!!?

I have an Electrolux Dishwasher, Model ESI 6104, and after the last cycle, there is about an inch of dirty water just sat in the base of the machine. I have removed and cleaned all the filters inside the bottom of the washing area, but the water has not drained.

Can anyone suggest anything? In the instruction booklet, it says to clean the siphon, but gives no indication of where it is (I'm not great at plumbing jobs to say the least)