Set Appliance State:
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Measurement:
Remove the Spark Electrode lead assembly and Electrode from the boiler.
Confirm Electrode lead and Electrode are in good condition.
Carry out a resistance check of the spark Electrode and lead.
Confirm Electrode lead and Electrode are in good condition.
Carry out a resistance check of the spark Electrode and lead.
Isolate as per TOPs P4
and refit as necessary