right hand oven not working on leisure rangemaster 110?

Hi, i've just bought a secondhand leisure rangemaster 110, which as been stood for some time i've given it a good cleaning and installed it, everything works fine apart from the right side oven, the ignition is working but no gas is coming through. theres no smell of gas either and no leaks. you can hear the knob click just like the left oven does just before the oven comes on.

what could be the problem

thanks

chris from wigan