How can I fix my Smeg Oven?

Our (top of two) Smeg Oven (SE10XMF) stopped working last night. It does not heat, the oven temperature light does not come on and neither does the back lighting to show the temperature and mode settings. The clock still works and the lower oven is still working fine. The temperature knob still clicks immediately when you turn it on suggesting that the thermostat is OK

The mode knob was difficult to turn for a while but is OK for the moment. Can you advise what the problem might be?