New Iphone 11 pro won't connect to internet after restoring from backup.

I'm setting up a new iPhone 11 Pro from my last backup from my iPhone 7 Plus. As I commence set up the phone connects to the wifi and the wifi symbol appears in the top right corner. Once as I restore from back-up and the iPhone boots up the wifi symbol disappears. In the settings it says the wifi is connected but no internet is available. Similarly 4G appears in the top right off the screen with 4 bars, but I cannot connect to the internet.

So far I have done the following:

• Phone on and off
• Wifi on and off
• Wifi deleted and reset
• Modem on and off
• Reset settings
• Reset phone, latest software reinstalled
• Finally restored phone to factory settings from DFU (twice)
• Used most recent backup from iCloud to set up
• Used week old back up from iCloud to set up

Always the same result. No internet connection and even though phone says (in settings) wifi is connected and 4 bars of 4G appearing on home screen (top right).