Hello there @Jon Davis, thank you for reaching out to us.
Firstly, you can find a list of our approved handsets below that will work fully with our network:
https://www.idmobile.co.uk/help-and-advice/approved-handsets
If the device isn’t on that list, then we cannot promise that all functions on the device will work correctly with our network and our SIM cards I’m afraid. Of course if the phone does indeed have Wi-Fi calling and allows 5G, then of course there’s a high chance that’ll work for you still.
Of course, you need to be within a 5G area within the country as well to allow for 5G signal to work:
https://www.idmobile.co.uk/help-and-advice/coverage#coverage-info
If you do indeed run into any issues with Wi-Fi calling or 5G with the phone, by all means get in touch, and we can see what we can do to help and advise further.
Kind regards,
Tyler