wickes halstead 102 boiler has no spark and no gas?

My Wickes Halstead 102 which i also believe is the Halstead Ace High boiler has no spark and seems to have no gas to the burners. Had a plumber take a quick look at it as it broke down on Christmas Eve and he was going away for a week and this is how i know about spark and gas. He seemed to think it was the PCB,fan or gas valve. The fan seems to run and it appears to go through the normal start up but it does not ignite and after a about 10 seconds goes to lock out. He was very brief and had not dealt with this model before so i am tring to get a head start before his return. Thanks