Hello Paul,Have you got a multimeter handy?
If the brushes are worn down that would also cause the same issue, as the motor is not turning to generate the signal for the tacho.Brush life is dependant on usage, however, generally the life expectancy under normal usage would be 3-5 years
Do not use the appliance with severely worn brushes
george, many thanks for your help today. The machine has done 4 washes since without problem.