if you click on a device within the home network map, it allows you to update details, or delete the device.
(just tested it on hh5b)
there is also a refresh which re-maps current devices, and theres a refresh on the dhcp listings page too.
Agreed, also the same for BT Home Hub 4 (Type A) | Software version 184.108.40.206.220.127.116.11.26
It just started working with the latest update (24/01/15) before then it has all been with no devices.
I have mine all named up to who's PC, Skybox, Mobile Device etc, and I just investigate when I see another unknown pop up on the list.
Would be nice to allocate them with custom Icons etc.