Tried the troubleshooting steps suggested by Garmin Support- still no joy.
- Remove any entries for the device in the 'Garmin Devices' menu of GCM, per "Removing and Adding a Fitness Device in the Garmin Connect App"
- Remove the device from the phone's Bluetooth settings
- Sign out of the Connect Mobile app
- Force-close the Connect Mobile app
- Toggle the phone's Bluetooth OFF
- Repeat the above steps on any phone/tablet the device has been attempted to be paired with.
- Toggle the device's Bluetooth OFF
- Power-cycle both the phone and the device
- Toggle the phone's Bluetooth back ON
- Toggle the device's Bluetooth back ON
- Open the Connect Mobile app
- Sign back into the Connect Mobile app
- Take the phone and the device outside (to avoid potential interference from other devices)
- Attempt to pair the device in the Connect Mobile app once more