Thanks Alister and Mark,
You've just saved me a fortune with the repair man (as well as sparing my embarassment if he were to see all the crud that I've just cleaned off of the floats and chamber!)
My machine was behaving a bit differently, it was half filling for the wash and then stopping. This seems to have done the job.
All you really have to do is undo the screw in the top of the clear plastic dome, take it off and remember the positions of the blue bits inside. Remove and clean these and the chamber that they came out of. Replace it all, ensuring that you have pushed the blue bits in as far as possible before putting the dome on, and switch on. I advise running the wash with no top basket and no bottom spinner thing for the first time as the filter then catches all of the detritus that you have dislodged, rather than pushing it through the spinner things first.
Martin, February 2007