Who is Dr. John Owen from A String in the Harp and what is their importance?

Dr. John Owen is one of the benefactors of the Wales National Museum. He is described as a slim, sandy-colored man with a sharp, clever face. He dresses like a country gentleman, often wearing a brown corduroy jacket with elbow patches and a dark green turtleneck. Owen is a shrewd businessman, who is obsessed with preserving old relics. When he learns that Peter may have discovered a valuable artifact, he becomes obsessed with it, even though he doesn't know if it is worth anything.