PSU for 970GTX SLI

[Digitalle]

I'm about to buy 2no. MSI 970's for SLI.

I currently have a Seasonic SS-550RM 550W Gold powering my HD 7970ghz.

Suggestions on the PSU I'm going to need?

Thanks

 

[Digitalle]

I can get an Corsair AX760 for £100, I'll go for that.