Port 47 is showing as dead, 48 as live, but the cable is in 47 not 48.
Thats the one - well spotted ..
47 is live, the pc is turned off, but there is no connection in 48, and yet there is a link light. In addition, a quick ssh session and
sho int br reveals
45 10/100TX | No Yes Up 100FDx MDI off
46 10/100TX | No Yes Down 100FDx MDIX off
47 10/100TX | No Yes Down 100FDx MDIX off
48 10/100TX | No Yes Up 10FDx MDIX off
49 100/1000T | No Yes Up 1000FDx MDI off
50 100/1000T | No Yes Up 1000FDx MDIX off
So the switch thinks that the interface is up..
Will wait for a quiet time and give it a kick over the weekend and see what happens then.
Thought maybe it was a new wireless networking standard that HP are rolling out!!