CDA CW448 stopped washing?

Hello
My CDA CW448 has developed a fault.
When a wash cycle is started, it drains any water away ok, then runs for a minute or two, then stops, I can hear a small clunk when it stops.
If it's left in this state, you can hear it trying to heat up water, but it isn't pumping any water around. It will eventually fill up with steam, but it never gets going as such.
I don't get any warning lights, just the normal lights.
I've tried resetting it, but no difference.
I've pulled the unit out, turned it onto it's back, and checked in the bottom sump pan, there's no water in there, and everything is super clean. The polystyrene float all seems fine.
If I then put the unit upright, and back into place, switch it back on, it will then actually do a wash which took me by surprise ... but never stops! I then can't do another wash.

Any help appreciated :o)