DRIVING down the highway, straight as an arrow, from Gloucester to Bristol one lovely English midsummer day, I turned right some 15 miles south of Gloucester and, topping a rise over a spur of the Cotswold Hills, came to a dead halt, so enchanting was my first view of the Vale of Berkeley. Below me the land fell softly away to the Severn leaving a watershed of unmistakable charm. Jenner called it "our evergreen valley," and no one ever knew it better than he. But what caught my eye, as it had with so many before me, was a tuft . . .