The pipex email admins have to manually set up mail forwarding. That needs to be authorised by the TalkTalk team that first need to verify you as the registered user.
I have no visibility of their workload but there has been no TalkTalk team presence here for a week now. All deployed on keeping vulnerable and key worker customers connected.
I just mention that so you're aware that there could be a delay until you float to the top of the queue.
Do you still wish to proceed with the request?
If so, just update your Community Profile to include in Personal Information (Click here) your name, current landline and mobile 'phone numbers and address with postcode (location). Then scroll down to Private notes to add the pipex email address with any relevant other notes and finally save changes.