You will need to confirm the last 4 digits of the Device Identifier on the box you wish to have set as primary.
This can be found on the Huawei box as follows ( maybe different on a Humax box) : Y Button > Settings > System Information > Device Information
With this information the OCE can identify the correct Set Top Box in the IPTV database.
For the OCE(TalkTalk staff) to look into this further please could you update your forum profile, if you haven't done so already, with the required information including your landline telephone number. This is only viewable by you and the OCE.
Just to let you know the forum is not a 24/7 realtime support channel and it can be 48-72 hours before you receive official OCE (staff) response. They usually work Mon-Fri 8am-6pm and deal with posts oldest first based on the timestamp of the last post on the thread, so try not to post until you get a response.
Regards