The dishwasher cycles down to 1min and then keeps trying to empty. It never does get there though. Water is still in the sump. Emptied this out once and it started ok again. Removed side cleaned out the sticky float switch. This was full of gunk. Noticed rear tank was partially blocked. Is this anything? Which is the outlet solenoid

SOURCE: Hotpoint dishwasher full of water after cycle complete

If the motor is running, the diverter solenoid valve is probably not functioning. It is attached to the pump. With the power off, take the solenoid apart and remove whatever is jamming it. Toothpicks are a favorite as are any large food particle. It may also be bad. Not the problem...you may have a defective timer or your outlet hose is clogged or kinked.

SOURCE: Neff dishwasher will not empty

Could be a kinked hose, diverter solenoid is jammed or burnt out. If the dishes are clean and the pump is working...then look at the above. If the spray isn't happening, the pump could be a problem. They are usually direct drive and you'll note that the motor isn't working.

SOURCE: Neff dishwasher continuously attempting to pump out water

Had the same probelm. Left the machine idle for a few days. By the time I found this solution, the water must have evapourated. The machine worked when I tried it. Underfloor heating probably helped evapouration. The original pump obstruction was caused by a piece or broken glass, so caution recommended when cleaning out the pump.

SOURCE: dishwasher not starting when door closes

What your saying is suggesting a water supply issue. The Model number you've given can not be found on the Neff website.

You will need to disconnect power, turn the water supply off (under sink or behind dishwasher), disconnect the water line, put the end of the hose in a bucket or cup, turn water back on slowly and make sure water flows. Turn back off. If water flows -

Then check that there is not a restriction in the water solenoid valve. If you know how to use a multimeter, check the water valve solenoid for continuity.

Plug the unit back in, and initiate a wash cycle, and watch for voltage applied to the water solenoid valve. If you get voltage, you should hear the valve open.
Power the unit off, connect the water line, and repower the unit. Check again if water does or doesnt flow.

Let me know what you find.

SOURCE: the dishwasher isn't draining properly. Not a

Sounds like you have a bad drain solonoid very common problem and easy fix.