So, the box will work over a wifi link.
I think you will find that the TP-Link devices use the mains wiring to carry the Ethernet signal, just like the BT minihubs. They extend Ethernet, and generate a local wireless hotspot.
The YouView box is therefore connected by Ethernet not wireless.
The unit I I have is a TP-Link TL-WA860RE. It is a single unit, there is nothing connecting the hub to the power supply.
The set up provided me with the usual terrestrial tv stations along with pause/rewind and unormal catch-up facilities. There may be additional services which require multicast, possibly their chargeable offerings which I wouldn't use.
It will work with non-multicast services, its multicast that causes the problems.
That's OK then, I just wanted the basics rather than subscription channels So I guess I'll stick with my wifi solution.
thanks for your help