2 sims showing in iPhone settings

[Friday]

I've recently switched mobile provider from O2 back to Sky, having been a previous Sky customer. On my iPhone 16  the Mobile Service page shows a 'Primary' sim and my own phone number, but there is also a second 'Mobile Data' line which shows a different number. I don't know where the second number has been generated, but I would assume this came from Sky at some point when I moved back to them and before I ported my number over.

I've tried changing the Mobile Data number to match my actual phone number but although I press 'Save', the number does not change. 

There's no physical sim in the phone. 

Do I need to contact Sky to get this changed or is there no issue as long as everything is working? 

[caesarome]

@Friday 

Have a read of this and make sure the primary number is selected:

https://support.apple.com/en-gb/109317

[Friday]

Ah.... just spotted that the 'Primary' number says 'O2' at the top of the screen, and the 'Mobile Data' line says 'Sky'....