How to fix my Potterton Lynx Boiler?

My boiler had a problem with the ignition. The insulation had come off the wire to the sparker and it sparked before it got to the igniter. So the boiler shut down after attempting to ignite the boiler for few seconds. I fixed this by repacing the wire and it worked well for a hour or two but now it wont even attempt to ignite the flame. The 'demand' light comes on and also the 'water heating light' and the little fan but no attempt is made to light the flame. Any ideas anyone?
Cheers.