Hi,
So I can look into this for you, can you answer the following questions :
Are on demand players such as Iplayer working?
Is the youview box connected directly to the router with a cable or do you use powerline adapters?
If powerline adapters used, are these directly into wall sockets, not connected via trailing extension blocks or via a surge protector?
Are you using the talktalk supplied router or your own router?
Thanks
Karl