Yes, I agree with everything you say above, they are very different. I also have both and also ridden them 'back to back'. I can also see that the top tube, seat tube and forks are at different angles. I'm just talking about the idea that a racey geometry would have a lower stack and a longer reach than a more leisurely geometry.
The only point I wish to make, is that the difference in geometry between the "racy" Ultra and the "sportive" Triban is either so subtle it is impossible to identify with a tape measure or they are essentially very similar geometry and they are sold to diffferent markets. I.e. £1,050 = racing, training, endurance; £300 = commuting plus the odd sportive.