Set Appliance State:
Gas Off
Set Multimeter to Resistance 
Isolate Mains Power to appliance as per TOPs P4
Remove the upper electronic flame control device
Remove the fuse (located inside the electronic flame control device, behind the terminal block)
Remove the upper electronic flame control device
Remove the fuse (located inside the electronic flame control device, behind the terminal block)
Measurement:
Measure the resistance of the fuse.
Resistance should be closed circuit.
Refit fuse and electric flame control device after test.
Resistance should be closed circuit.
Refit fuse and electric flame control device after test.
Isolate as per TOPs P4
and refit as necessary