Make sure you turn off "smart setup" on the Homehub.
See link how to do that.
http://bt.custhelp.com/app/answers/detail/a_id/44328/~/what-is-smart-setup-on-the-bt-hub%3F-how-can-...
Some devices have a problem with the Homehub dual band having the same SSid (name). You should try splitting them.
See links
http://bt.custhelp.com/app/answers/detail/a_id/56419/~/how-do-i-split-my-bt-hubs-ssid-%28wireless-ne...
http://bt.custhelp.com/app/answers/detail/a_id/44798/~/i-have-problems-connecting-5ghz-and-dual-band...
Which hub are using. Can you post stats
Another possibility if you're using a smarthub is to turn Authoritative DHCP off (Advanced>My Network >IPv4 configuration).
Maybe its just my hub or devices but I've found that Authoritative DHCP can cause contention between the hub and the device