Originally Posted by JessicaB

If they are both on separate tickets you will also need to reclaim any hold bags and then check them in again. IB will only through-check bags if they are on the same booking reference. The non-EU immigration lines were long when I transited recently, it took maybe 45 mins to get through immigration. But that should mean that by the time you are through your bags are available. Then add, say, 15 mins for the walking. The lines at check-in are also long, it took me 30 mins to check-in, and that was on a J flight. So I would leave a bare minimum of 2 hours and 30 mins.