As the Philips Hue Hub v2 does not come with a PoE option (Power over Ethernet), I decided to look in to a way to power it via PoE.
The Hub sits about 1 meter away from the switch behind the TV (Netgear GS108P) and I needed to free up a power outlet on the extension for another device.
The device calls for Power from the switch and then splits the power away to the DC Plug. Only pins 1,2, 3 and 6 are wired on the RJ45 plug for network.
The adapter then steps down the 48v to just 5v and provides that via a 3.5x1.35mm DC plug (Be careful there are other voltages available and anything higher could damage the Hub).
ebay came to the rescue and a search for "3.5mm x 1.35mm to 5.5mm x 2.5mm adapter" produced this little adapter for a measly £2.39 (inc P&P).
Job was done. The Philips Hue Hub powered back on, being powered from the switch and I had freed up a power outlet on the power extension outlet.
The issue now arises that the DC plug on the PoE splitter is too small, there is an adapter in with the PoE splitter to take it up to 5.5x2.1mm but that is still a fraction to small (it may fit in to the Hue Hub if you push it really hard - but I strongly advise against that).
And that was it. Remove the existing power adapter and network cable from the Hue Hub. Connect the network cable coming from the network switch to the splitter, then place the DC plug from the splitter (with the 5.5mm x 2.5mm adapter on the end) in to the Hue Hub and the connect the splitter to a PoE port on the switch.