Set Appliance State:

Gas Off
Isolate Mains Power to appliance as per TOPs P4
Note:
Read Technical Services Bulletin ( REF: E/T/17/02 ), regarding burner, electrode gaskets.

Observation:

Remove the burner to inspect for any signs of damage or dirt.
Note:
If you have previously checked the spark electrode (by removing the burner) and the burner appeared satisfactory select the "Burner condition satisfactory" option below.