Kenwood ck 405 intermittent fault

So the main (fan oven) is not functioning as it should. When I turn the function knob that controls the light/fan/oven/grill the internal light and oven power/temp indicator light flash intermittently as if there is a short on whatever setting it is on. It’s only doing it occasionally but appears to be getting worse. The smaller conventional oven is working fine. I’m guessing as it is doing it when I just select the light function it isn’t the thermostat or cut out. I’m thinking control or pcb problem. Any ideas?

Cheers.