Ok, say I ended up getting a CSM750, not the CX750.
It's an improved semi-modular, Gold-rated version of the CX750 -
http://www.corsair.com/en/cs-series-modular-cs750m-750-watt-80-plus-gold-certified-psuI thought it would have 4 separate PCIe cables but there are in fact only 2 cables, with 2 PCIe plugs on both....

Should I 100% get a refund and buy something else, or will the above be ok?
I'm at the stage now where I just want to get it powered and running.