Not specific to Leeds. / Bradford but we always get to an airport 2 hours before departure even if it's not strictly necessary. This allows for getting through security, which can be slow, finding the toilets, information boards so you know when your flight is called etc. They usually put up the boarding announcements 45 minutes before departure giving you time to get to the gates etc. If you have an hour to spare you have time to get a coffee or a sandwich , sit and read the paper or whatever,. If you are anxious about timing, it's always better to allow plenty of time rather than be in a rush. Airports are quite nice places these days with lots of shops and cafes and I don't mind spending an hour waiting rather than worrying about missing the flight.
