Cowboys haven't played in London since 2014, Steelers since 2013. Divisional games seem rare, buy I do recall Jets/Miami in London a ways back. London still getting Junior Varsity talent match ups when it comes to scheduling it seems, while our Jets, ironically, still feel like they belong in Pop Warner. London gets all the Jet, Jaguar and Panther games it can handle though!
Divisional games should never be played overseas. Those are the most important games on the schedule and no team should be forced to give up a home game against one of their rivals.