thanks for the suggestion. I'll give it a go.
Regarding the cables/lights etc
> The ports are intermittent you say? Mine is currently 5 years old and hasn't gone wrong yet! Have you checked the ports for any dirt or debris? This will cause bad contact with the terminals of the plug and socket. I know that's an obvious thing but i have to suggest it!
> Are you getting a solid white LED at the base of the unit and is WiFi still working? It's also possible your ethernet cable(s) are faulty so are there any others you could try? Although if the built in Gigabit switch is genuinely failing they are of course at liberty to replace the defective Hub!
I've tested the cables with a (low frequency) cable tester, and they are all good, and work on other devices. The worst port on the hub shows no lights at all. The other ports have periods of say 1h when they appear to work as normal, but then another period where there are no lights (maybe some temperature related electrical issue inside). I've tried swapping the cables about and after you said, inspecting the sockets for dirt (nothing helpful there). The WIFI is so far ok.