Indesit WA155 Starts but Dial spins constantly whilst discharge pump runs?

Indesit WA155 Starts but then the Dial spins constantly whilst discharge pump runs

When starting a new washing program it starts to fill, rotates continues to fill as per normal but then is starts emptying, the pump goes constantly and the dial starts clicking round endlessly. If left it carries on in this state, pump going, dial turning.

I've tried spinning the dial round lots, turning it on and off, it still does the same thing.
I've also tried to start it at the end of each of the program cycles then turning it off with button as the light flashes repeatedly very quickly (supposed to reset it?? Found that tip on the web) None of this has helped, it just starts as normal again before doing the same trick.

Can anyone tell me what it might be? Should I try and replace the dial (it's £20) or is it likely to be one of the sensors playing up causing it to do this.

Any help appreciated.