WIA 101 (UK) stops mid cycle?

My WIA 101 (UK) washing machine stops mid cycle and the door remains locked but nothing happens. The only lights lit are the green wash light which is solid and the green rinse light which flashes. The only way to release the door is to unplug it at the mains. Obviously the drum has drained of water at this point but the washing is still soapy. Any suggestions welcome.