Set Appliance State:
Gas Off
Set Multimeter to AC Volts 
Isolate Mains Power to appliance as per TOPs P4
Gain access to terminal strip
Gain access to terminal strip
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Is there Mains Voltage present across the L (Brown) and N (Blue) terminals on the Appliance Terminal Block?
Isolate as per TOPs P4
and refit as necessary