I assume you have a permanent pilot light on your boiler and its not an
electronic ignition! You are trying to relight the pilot and you can
see the spark from the manually operated spark generator through the
sight glass, Yes (I assume) The pilot wont light. You have obviously
ran out of gas before due to the quantum meter and managed to light the
pilot yourself, ok. You need to get it looked at, better still get it
serviced, and after its serviced get the engineer to show you him
lighting the pilot from cold, to ensure you can relight it yourself
when your credit runs out again.