You may disable the Cosy and revert to your original heating controls on the wall (e.g twist dial thermostat) by following the steps below: 

1. Press the OVERRIDE button (in the middle) on the Cosy switch so that the Cosy goes OFF 
        
2. Turn your original twist dial thermostat to your preferred temperature                                                        
3. Set the boiler timer to your original heating times for 'on' and 'off' e.g On all day, On Twice                                                                                                                                                                                
4. Once you have confirmed your original heating controls are operating the heating correctly you can unplug your Cosy