Hi ​@JayW 

I am afraid that you would not be able to transfer your iD number from one iD plan to the other. You would need to upgrade your old plan to a SIM only plan to retain your number.

I would suggest to return the new SIM only plan and process an upgrade - How do I return my order? | iD Mobile Community

I hope this helps.

Hi Sian...thanks for that advice. There is an issue it seems when I log in to my account and try to upgrade from an expired handset account to a monthly sim only I was logged out so I inadvertently set up a new account and phone number. That has now been cancelled and I have been upgraded by Reon who then put me through to customer services where Sonia cancelled my earlier account and new sim. I have been able to keep my number and my account remains live. So the issue seems to be that I could not upgrade whilst logged into my account…? 

Hi ​@JayW  glad you got it sorted! Have you been able to log back into your iD account now?

Thanks Sian...yes to log-in which now shows my new plan having been activated remotely. All good. Jay