If they take off with the flaps set at 5 degrees, when the flying pilot calls "flaps up" the other pilot would move the flap handle to the "up" position. If they had been at a light weight they may have taken off with the flaps set at 15 or 22. More flaps allows the plane to fly at a slower speed but you wouldn't retrack them all at once. If they had taken off with the flaps set at 22 they would have climbed up to 3000 feet above the airport and then lowered the nose some to allow the speed to increase. As the speed picked up to a number based on the takeoff weight, the flying pilot would have called for "flaps 15" and the other pilot would have moved the flaps the 15 degrees. As the speed increased further, the flying pilot would have called for "flaps 5" and finally "flaps up." Since the runways at LHR are long and they're going half way around the world, I'd guess they'd only use flaps 5 for takeoff and the call would be "flaps up" and the non-flying pilot would repeat the call and move the flap handle to the up position.