First of all I apologise in advance for my sheer stupidity.
Proc:- i7 3770k 3.5Ghz @ 4.5Ghz
mobo:- Gigabyte GA-Z77X-UP4TH
Cards:- 2x 680 GTX (KFA2 both exactly the same version) "sli"
I have scoured the interwebs for help with my sli issue. Both cards are detected in device manager as working without any alerts for any issues. Both are being detected on the nvidia control panel however there is no option for sli. Where the sli configurator option should be there is the option "Configure Surround, PhysX".
I have tested each card indiviudally and both are in full working order. I have uninstalled and reinstalled the drivers during this process for each to rule anything out. Also I have tested several different SLI bridges in all configurations.
I have an Asus sound card in the lower slot which I don't believe should affect anything.
The system was built by overclockers UK and as much as I value their skills I can't help but think maybe there is something that was overlooked their end as I have made no changes (as yet) to my system.
On looking at GPU-z I can see the Bus Interface is different for both cards. They are as follows:
I decided to go with my gut instinct and leave both graphics cards exactly where they are. However, I did remove the sound card and.... low and behold, Sli is live and kicking.
Seems like the sound card was dragging the second card into an x4 state. Bizarre.
I couldn't find a suitable answer in all my searching on the internet regarding this problem. I hope that others find their answer as straight forward as this solution was. I use a head set and mic anyways at all times so I won't really miss the sound card.
Thanks again for your help Jack and to all of the Tomshardware community.