Thanks for the great responses. There were some good points that got me thinking, and looking back at the slides. First, it wasn't often sunny in England. The few times there was clear, unobstructed sun were in the late morning or mid afternoon. So it was high enough to be strong, but low enough to be right behind me and shining directly on the subject. The subject is the other part. Most of the shots were of buildings, with vertical sides reflecting the light straight back. The light-colored stone and brick reflected a lot of light, too.

This was very different from shooting landscapes. Foliage is much darker and horizontal surfaces don't reflect as much light toward the lens. I should heve remembered that a shear rock face will typically meter at least a stop brighter than the forest below it.