The walkthrough states:
Crune Museum: Talk to Lobineau about the manuscript. The knight is Spanish and the crest is of the Vasconcellos family.
Villa de Vasconcellos: Click on the red arrow of the airport on the map. Click on the Spanish flag at left.
George looks at the seal above the arch.
If the flag isn't showing up, it sounds like you must have missed a step in the previous section. See if you can go back and figure out what you might have missed.