Thanks. To be honest, I am not sure what piece of kit is emitting the WiFi signal, but which ever it is, it keeps dropping out intermittently. The wired connection continues to work, but the WiFi connection disappears. Sometimes for a minute or so, sometimes for a couple of hours.
It was generally fine until the last few weeks. So I don't know if this means the Hub needs replacing, or these old WiFi extenders...? Or if there is anything else I can do to check what the problem might be?