Bosch cooker hood switches?

Please can someone advise how to get at the switch board for a Bosch cooker hood E-Nr DKE 995 A GB and FD 8009.

The lights have stopped working and it is not the bulbs. I have replaced them several times before and putting new ones in now does nothing. The switch for the lights appears to be working as the hood still bleeps when you press the button but the lights do not come on.

Bosch themselves do not have an engineering manual for this model any more and I can find no way to access the rear of the switches. There must be a way to dismantle the hood but I cannot find it. Please can someone help. Thanks.