Plusnet Hub 5 router now only LAN connects at 100Mbps and not 1Gbps

[#1]

My router used to provide 1Gbps on all four RJ45s. It now only connects at 100Mbps. I've tested this with two different PCs with 1Gbps LAN cards. I assume the router has become faulty? Any ideas on the fault and how would Plusnet swap this?

[#2]

Have you tried swapping the cables. I have had similar problems (different routers) which have gone away after either removing and replugging the cable, or swapping the cable for a new one.

Gigabit Ethernet needs all four pairs to be  good. 100M only needs two pairs. If one pair has got a bad connection, then I think if falls back to 100M.

[#3]

Not to be picky, but its only the Hub 1. or BT HH5 that has 1Gb ports. Might be worth a reset oh your router.