Just in case anyone had the same issue as me, the Connect-X Windows 7 x64 drivers seem to work fine in Windows Server 2012 using this card. I've pinged and copied a few files around so hopefully when I setup my storage it keeps up!
Maybe I downloaded the wrong W2K8R2 ones but even though a comparison of versions were correct in control panel the W2K8R2 drivers were dated 2009 in the program files location whereas the Windows 7 driver set was some time in 2010.
Cheers
Drew