Hi Ashleigh
I arrived back in Bristol yesterday and had exactly the same problem with my phone i.e. couldn’t get a signal.
Turned my phone on and off, changed from 4G to 5G. Turned the phone on and off again, still no signal.
Changed from 5G to 4G again turned the phone off and on again but still no signal.
My wife’s phone connected instantly.
I drove out of the airport and after about an hour I got a signal so there must be something wrong with my settings.
Is there a way I can check what my network settings should be for international travel?