Rangemaster 110 Gas Oven sparking all the time?

3 months ago i bought a timer and fixed it, no problems. My Gas Rangemaster 110 now has decided to confuse me, the igniter continues to spark for the right hand oven all the time (the oven used 90% of the time) unless the other oven is on! My only way round at the moment is to keep it off at the mains elec (to stop it sparking all the time) and just switch it on when i want to use the oven and then turn on the left oven which then stops the right oven sparking! Any advice on what is happening or what part i need?