Thanks for the info @TheCakeIsNaOH.
I never even thought that it might be something that could be solved with a BIOS update, I figured it was a later hardware revision I needed.
Great suggestion on using a cheap X5500 series CPU to boot the board for a BIOS update. I will look into that because I think I can get a suitable CPU for less than the cost of returning the Supermicro board. I have a PSU that will power the Supermicro board so if I can get the working with the X5680’s it will save me that expense too.
Thanks for your help
Shecks