the problem with these pre binned chips is they seem to be binned at silly high voltages like 1.4+, so the temps would be pretty insane on a HTT chip at those voltages.
I think most CL chips could do 5ghz at 1.4v, even poorly binned ones, so I am not convinced personally of the merit of buying a 5ghz binned chip at 1.4v.
Before I get myself in trouble, I know I dont have 100s of chips in front of me to confirm my claim of "most chips could probably do 5ghz at 1.4 or higher"
I do understand OCUK's stance tho, whatever the merits of these binned chips, if they selling the system with a chip running to a particular heat profile, they will want to make sure that out of the box its running at parameters they are prepared to support with warranty.