Just an update, from my January 12, 2015, 12:11:24 PM post..
Turned out to be a Cat5 Ethernet cable from a wall socket to a basic D-Link DGS-1005A switch, it turned out to be an intermittent loss of connectivity, perhaps caused by changes in ambient temperatures in an room that is not air conned or cooled, anyway it was not consistent, only confirmed it as I was watching the switch as it lost connectivity, a jiggle and it was back, an hour or so later gone again.
Changed the cable and all problems have now gone, hopefully never to return
![Smile :-)](/Smileys/default/smile.gif)
so as always make sure the easy basic things are right first before going digging
![Smile :-)](/Smileys/default/smile.gif)