Set Appliance State:
Mains Power Off
Set Multimeter to AC Volts 
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
On the 24 hr clock, to the left of the Control box, measure the voltage across the brown leads (live) and the blue leads (neutral).
Expect mains voltage.
Expect mains voltage.
Isolate as per TOPs P4
and refit as necessary