Hah. To swap eSIM on O2 in the UK, you have to order a physical pack that gets posted to you with the QR code in. There is no way to get the code to appear on a screen you can scan with your camera, or in an app on the phone you can transfer to the phone’s eSIM manager. It’s so dumb.
Fugu. I’m far too much of a coward to try it normally.