BT Broadband Voice and BT Hosted VoIP line names cannot be synchronised across Webcare and the VoIP Portal.
Following the upgrade, from Webcare to the VoIP Portal, you will need to reset the names of lines via the VoIP Portal's Manage my lines screen. But only once. For details see How do I change a line name?
If you have made any changes to the line names on Webcare during the dual running period, these will not be synchronised with the VoIP Portal.