Bosch integrated model SGV55M03

Question

I have a problem with a dishwasher - its a bosch integrated model SGV55M03 only 3yrs old (would be use once a week only)- the outlet is connected to the waste disposal.
The drain motor keeps running continuously - reason being the float valve in the base is up as there is water in the base (under the unit itself not inside the d/w). When this is emptied (pulling out integrated machine and turning on its side) it then works for two cycles but then fills in base again.
A suggestion to solve this was that the outlet pipe (as the water in the base seemed soapy - but this maybe due to soap residue in the base not the water itself) was not high enough - looped - and so water was running back in but I tried this and it did run for an extra cycle but back to same problem again.
I would open the machine but I don't have a spec and for some reason could not locate the screws to remove the base
All assistance needed