Set Appliance State:

Mains Power Off
Turn Hot Water Tap On
Gas meter test dial will have to be viewed during ignition sequence
Gas On
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Reset appliance by depressing reset switch.
Observe gas meter test dial, does it show that gas is flowing during the ignition sequence?
Note:
There will be approximately 15 seconds until the first attempt at ignition, then there will be a second attempt after 25 seconds then a third after 50 seconds. Then appliance should then go to lock out.
No other appliances must be in use during test.