If you have the stick-on telematics device, you need to keep Bluetooth switched on. This is a condition of your insurance.
For the stick-on device:
Your phone must be on, paired with the device and in the vehicle when you drive
Your Bluetooth must be switched on when you drive
You need to keep location services and mobile data on when you drive
These conditions apply to all drivers on the policy.
If you have the plug-in device, you don't need to worry - it has its own network that it uses to send us data.