They are not the only sf authors with a recent Clare College connection: I knew Rebecca Levene rather better than Marcel Theroux when we were students, though she was in the year below us. She is best known in fandom as the former editor of the New Adventures of Doctor Who but is also an author in her own right, and has glancingly referred to her past studies of anthropoliogy and social sciences in her pseudonyms ("Evan Pritchard" and "Carla Marks").
Peter Ackroyd is also an alumnus, but rather before our time. I see also that Nick Harkaway who had a nomination for last year's BSFA Best Novel would be a contemporary of Miéville's, and comics artist Sonny Liew appears to have been at Clare several years later.
I read The City & The City a couple of months ago; Far North is in the pile of books to read.