I have the same issue too....
Wifi devices report "Connected, No Internet"
Forget and Reconnect allows the device to work for a short while.
Pinging the wireless device clearly deomonsatrates bursts of ICMP packets being dropped. Nothing in the HH6 Technical logs to account for the dropped packets.
Some applications such as Facebook Messenger become aware of poor networks.
I have had a new HH6 but it did not resolve the problem.
I moved your post as previous thread over 2 years old
if you have hh6 have you turned of smart setup http://bt.custhelp.com/app/answers/detail/a_id/44328/~/what-is-smart-setup-on-the-bt-hub%3F-how-can-...
have you split the wireless networks http://bt.custhelp.com/app/answers/detail/a_id/56419/~/how-do-i-split-my-bt-hubs-ssid-%28wireless-ne...