When you fly out from LAX there should be an option to choose between LAX - Gate 4 and LAX - Gate 5. London, England is located under Gate 5. (I'm assuming any new locations in the future will also be accessible from there.)
I'm having the same problem as well. I haven't had any quests since the Latin Lover one, and the La Rue Interview was the only thing I was able to do in Paris. I thought things would change after the London update but no luck. :(