Re: Fixed it ages ago.
My fix was to replace the HH5A with a TP-LINK TD-W9980 N600. It was a £66 pound fix, but the reduction of grief from the family made it worth it.
It was simple to install and get going. I took all the documentation and the provided CD mini disk and through them away. Install the hub, navigate to the suggested URL (http://tplink.local I think) and turned on the network. You need a username and password. The username is email@example.com and any password will do. Add a password for the 2.6G and 5G wifi networks and your done.
This plugs directly in to the wall socket, mines next to the master socket.
And now, for the first time, I can have DHCP with a set of DNS resolvers that I choose, not which BT force on me. I wish I had this hub years ago,