Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Disconnect leads from both gas valve solenoids

Measurement:

Test 1:
Measure the resistance across the pilot solenoid connections (left hand solenoid)
The solenoid resistance should be approximately 2.1kΩ.
Measure the resistance from either of the pilot solenoid connections to a suitable earth point.
Resistance should be greater than 1MΩ.
Test 2:
Measure the resistance across the main solenoid connections (right hand solenoid)
The resistance across the solenoid should be approximately 2.1kΩ.
Measure the resistance from either of the main solenoid connections to a suitable earth point.
Resistance should be greater than 1MΩ.