You cannot light the pilot manually, it is electronic ignition. If the boiler will not light, the most likely cause is the fan at the top of the boiler, where the exhaust fumes exit the property, being seized up due to lack of lubrication. This is easily fixed by undoing 4 screws on the round cover, carefully pulling out the fan unit and dripping some oil on to the bearings. Turn off the electric supply to the boiler first or call a competent person to do the procedure for you.
Bernard
January 2010