Feckin Gremlins.


 So... Disconnected one GPU and rebooted. - Locked in with the pool no probs.

 Rebooted with the 6th GPU and now it has connected and is mining.. Just as I was looking for a hammer to smash the fucker!!!!


 Thank you all who helped resolve this story..


Just to clarify... currently have 6 x GTX 1070 mining at 160 MHs using a Corsair RM 1000 PSU