Dometic Series 10 Fridge

We are having an issue in a Swift caravan with a Dometic Series 10 tower fridge specifically the fridge door open alarm. After all night without use the door open error (W10) sounds the bleeper and takes around an hour to clear. The bleep itself can be silenced (after several attempts) from the control panel but light stays on and the command panel also shows a door open warning, it seems particularily bad when the van or outside temperature is low as now 11* in N Wales.  Once the alarm clears door can be open and shut without issue until another prolonged closure. Grateful for any suggestions