Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Unplug the HT lead from the spark electrode

Measurement:

This test can be carried out with the wires still attached to the spark generator.
Measure the resistance of the spark electrode lead, expect approximately 1kOhm.
Inspect the lead for good overall condition.