Hi james
Firstly I am no expert ! I just have exactly the same problem as you with the same dishwasher.
I have taken the main filter off and drained the base .
I have also taken off the valve that is secured by a wire strap. You will see a small impeller there. That is where I think my problem is ! as it does not run freely when i flick it with my finger - so in my case I think I will need the Meile man unless I can get behing the inpeller to really free it up ! This could be your problem so try and free it up . it may have some thread or the like around it restricting rotation. If that doen't work then you are in the same boat as me right now. Which means I have to drain it myself after every wash ! until it is fixed.
I hope I have been of some help !
David
July 2010