The majority look to be travel books. I think theres a few 'coffee table' type lonely planet photography type books in there for good measure too.
There's a bunch of Bradt guides (The ones which are green with white tops are most identifible - though different editions are in different colours). They are a series of books for places which tend to be more off the beaten track than even lonely planet. I doubt a designer would pick those tbh - they are for a certain market, which Ben definitely would fit into.
There are LOADS of lonely planets - the navy blue tab with logo is easily identifible on some and theres the traditional all blue spine too. Given he was previously the picture editor at Tatler, lots of photo heavy travel books make sense too. Not necessarily for reading or reference regularly. The black shelf looks theres a lot likehas a lot of books with the black spine of Lonely Planet Photo books.
I think I spotted an SAS book in there too. And I think the majority of the white books are books about adventure / travel too (they have a certain look - I've got a bunch of books on the subject and they look different to my other books even from the spine.
And if they are all travel type books they ARE in some kind of order really anyway.
I don't have anywhere near as many travel guides as him, but I can spot them a mile off. (Nerd alert).