Set Appliance State:

Mains Power Off
Thermostat turned to Frost position
Ensure that the ambient temperature is above 5 °C
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

With the ambient temperature above 5 °C and the Thermostat Potentiometer in the Frost Protection position the boiler should not run its ignition sequence and operate.
Note:
If ambient temperature is below 5°C then boiler operation would be considered correct.