Were do you find leonardo da vinci in ins creed brotherrhood were he sits on the bench and u buy gloves?

If you have ped the point in the storyline where you have talked to Leonardo once, then you can find him at certain benches in Rome. It will be marked on your map with a symbol that looks like an L in a diamond. Turn off other map markers if you are having trouble finding it. There is a similar map marker that sends you to a memory to destroy one of Leonardo's machines, though, so move your pointer over the marker to make sure of what it is first.