I have a Leisure Gourmet Classic double oven. The hobs, the grill and the upper oven all work fine, but the lower oven suddenly stopped producing any gas. I turn the knob and the austomatic ignition s

I have a fairly new Leisure Range 60 Gourmet Classic cooker with double oven. The hobs, the grill and the upper oven all work fine, but the lower oven suddenly stopped producing any gas. I turn the knob and the automatic ignition spark continues to spark indefinitely, but there is no gas coming out. As mentioned, gas supply to all other parts of the oven is fine, just no gas supply to the lower oven. Looked in the manual, but no mention of such a problem. The lower oven is self igniting. Push and turn the knob and the spark automatically sparks until there is ignition, but no gas. Any ideas