Thanks all, changed the name of the new Tello SSD and works a treat.First, write down SSID of lost Tello, exactly as it's spelled.
When you get a new Tello:
- Turn it on
- Connect phone Wi-Fi to Tello hotspot
- Start OEM Tello app and go to Settings -> Wi-Fi
- Rename SSID to that of lost Tello
- Don't forget, the password also has to be exactly the same
- Exit all the way out of the app, turn Tello off
- Leaving the extender out of the equation for now, restart Tello and phone Wi-Fi should connect.
- If it works, try it with extender next... that should work too.
Will purchase a tracker of some sort.