Amazingly my Legacy Three UK SIM is still working. I planned to give it up since I have a data-only eSIM that works in the UK. However, I got a reminder e-mail from them so I figured why not try. I turned on my old phone. I did not send a text but somehow it generated a 0.15 charge so I guess that is good for another 6 months.

I chatted with a rep and was told the Old and the New Paygo are the same and support Wifi Calling/VoLTE.

I converted to eSIM but it was a two step process - you first order an eSIM and then you activate it.

The system still cannot handle a non-UK address.