Gemma, like TLC, it's been a long time since I played this game, but I don't think you have to worry about the torch at all--it seems to me that after you lit it, you just go on with the game.
You will probably need that second torch too--there are certain things that need to be done and you can't finish them if you run out of light.
Btw, if you are ever looking for a walkthrough, the official name of this game is
Sherlock Holmes: Mystery of the Mummy, and that's how it's listed in our walkthrough section...