how to re ignite the pilot light on a worcester bosch 230 combi rsf boiler?

I am having problems with the re-ignition of the pilot light on the worcester bosch combi boiler 230 rsf. I have tried the guide on the users operating instructions, by setting the temperature control to max and switching the mains on, but no burner light comes on, please, please, please let me know if there is something I am not doing right or ???? need to do to get the burner light to come on, it seems simple but can't get it to work.
Thanks,
Mo