i had this prob it might be different because i have a tank in the garden .but i had to pull a valve on top of the tank its like a plastic plug before the pilot would light took me ages to figure it out if your mains its prob no help
ash
September 2009
hold the pilot button on the gas valve for a few seconds, press the piezo igniter button continuosly while still holding the pilot button until it lights. continue to hold the pilot button for about 30 seconds before releasing it.