Isolate Mains Power to appliance as per TOPs P4
Observation:
Remove the Diverter Valve Motor Unit from the Diverter Valve.
Does the Motor return to, or is it in, the HW position (both types of valve are spring return)?
Does the Motor return to, or is it in, the HW position (both types of valve are spring return)?
Isolate as per TOPs P4
and refit as necessary