Hmmm. You are right regarding the Corsair having only 2 PCIe connections and therefore not being able to support the GTX in SLI.
To tell you the truth, I will never be running SLI anyway as I will only ever be purchasing 1 GTX, 2 is overkill for me.
The Corsair is now £10 ($20) cheaper and according to Johnny Guru, is better built, more efficient and has a 5 year warranty. Corsair it is then!
Thanks for your help guys!