Control panel / fridge not working

[Martinandjenny]

My fridge stopped working (I left it open during the heatwave, next time I couldn't turn it on) the fridge temp error light flashed on the control panel. My local camper van garage took a look but this made the control panel stop working completely! They have established that an external 12v current makes them both work (phew) so the issue is a sensor somewhere is faulty / needs resetting. Online fault finding doesn't work as Westfalia / MB don't publish the electrical info and wouldn't share info with the garage.
MB garage won't help -has anyone had this problem? Can you recommend a Westfalia specialist anywhere near Bristol ?

Thanks
ps. don't leave your fridge lid open to air in hot weather