Thermalright Peerless assassin would be another option - again I can't link as OCUK don't carry them, but I have the smaller assassin king version and it's just about able to keep my 5950x at bay, although a bit hotter and noisy than I would like.
I only bought it to get me through some troubleshooting and while I clean down my watercooling stuff, but I'm sure the peerless version would be more than sufficient!
As a bonus they are also not that tall (157mm) so should fit in most standard ATX cases