Under the fire, you'll see the boiler's gas valve, 99% of the time you need to remove the bottom flap of the fire.
All the controls for lighting it can be found on the gas fire with the ignitor to the right if memory serves me correct. BTW, time for a new boiler; so start saving... Not many majorca's left now.
-> thermgas.co.uk
ThermGas, December 2006