I have a BT SmartHub 2. I have 2 Ethernet connections to 2 bt recordable boxes. All works ok during the day and the evening, but in the early hours ( after midnight ), the boxes appear to have lost the connection from the hub. When I try to switch on the boxes, say at 0200hrs they have to reload themselves so that they will work. This happens every night.
Bit of a long shot, try extending the DHCP lease time in the hub to maximum.