So he narrows the field to people from the UK at Crypto2011."
Not Singapore, NZ, Australia, Hong Kong, India or any number of prior British colonies that use British English and spellings instead of American? (How about China? Not sure what English version they use, but wouldn't be surprised it's Brit).
Unles there was no one from any of those countries at Crypto2011, then it looks like he excluded up to 2/3rds of the solution space.
Also, I wouldn't be surprised at a skilled cryptologist who wanted to stay incognito faking his spellings to throw people off. For example, I'm not a cryptologist, am American, am not trying to be incognito, and enjoy using British slang and spellings occasionally anyway. And this guy Clear sounds like he's enjoying taking the piss out of the reporter.