You got incredibly lucky as you must have missed the usual BA93 arriving at the same time as the Saudia, Etihad, PIA, Air Transat absolute gong show. Can easily spend an hour walking interminably around tensa barriers to get to hand in your slip at the first check. A few weeks ago they had changed back to actually allowing Canadian passport holders to go through a separate line finally which meant only about 25 minutes. But what other airport in the world do you have to show a receipt at 3 different stops to get landside. It's a really bad joke