Welcome to the Community, @KeithAmbler
As @XRaySpeX has mentioned here, chances are you can ignore this, as occasionally your phone can continue to read the temporary number from your SIM after a port.
Provided the correct number comes through for calls and texts, this shouldn't cause any issues.
Sometimes you can amend this by checking your contacts and seeing if it has assigned the temporary number to your own contact.
It's worth trying to remove your SIM, restart the phone then reinsert it too, as this can sometimes force the internal details in your settings to update.
Peter
