Many thanks for the 'tipping' tip. Clearly this works for most people, but in my case the problem was due to excessive limescale buildup inside the machine and tipping the machine did not solve it.
If the tipping does not solve it for you, you may have to give some of the pipes a clean. It only takes about an hour and doesn't need any special skills.
Follow the suggestions below (esp. Nigel 2009) to remove the left side panel.
*** Make sure the electricity is off at the mains mefore going any further ***
You will see the large clear plastic pipe unit towards the rear of the left side, and a smaller separate clear float unit at the bottom of the left panel, towards the front of the machine. This contains the microswitch that controls the pumpout, and the vertical red lead bar connected to the 'famous' float swutch. If the pipes and channels inside these clear plastic units are very clogged, you should unclip them for cleaning.
Turn of the water supply first, have a tray ready to catch the spills, and take some photos first to remind yourself how it goes back together.
You will also have to unplug the microswitch cable to remove the lower float chamber. Remember which way around it goes back on.
In my case the narrow drain channel connected to the red float chamber was blocked, and the float always rose up, so switching to 'pump out'.
There's a plastic pipe connected to the bottom of the lower red float chamber. This disappears under the front of the machine. I pulled it out and cleaned it - it was completely full of limescale and so the flow was backing up all the time. But be careful - if you pull out this tube it's a bit of a job to reconnect it to the machine. You need to tip the machine back about 45 degrees and take off the white plastic fascia strip under the front door, this exploses a metal plate with 2 fixing screws. Undo this and let it hang loose on the wiring harness. You can then get your hand under the machine to re-fix the pipe.
The moral to all this - keep the salt filled up to soften your water and use a de-scaler regularly. I have now learnt!
Paul
October 2012