NEFF U1721 has stopped working

I am looking for some advice please. We recently moved into a property with the above appliance fitted. It inexplicably stopped working yesterday. It was not on at the time. Essentially there are no visible display lights, nor do the switches turn the oven on. I automatically assumed it must be the fuse in the wall switch so I replaced this but it has made no difference. The ignition spark to light the gas still works (it doesn’t with the fuse out) but nothing else does. All the other appliances/switches in the kitchen are working fine. We phoned the NEFF helpline but they charge £100/hour before spare parts! Is it possible this might still just be a fuse issue or is there something more serious that we need to get a technician in? I am reasonably safe from a DIY perspective.