FROM BETWEEN TWO trees at the crest of the hill a very old man watched, with a nostalgic longing he thought he'd lost all capacity for, as the last group of picnickers packed up their baskets, mounted their horses, and rode away south-they moved a little hastily, for it was a good six miles back to London, and the red sun was already silhouetting the branches of the trees along the River Brent, two miles to the west.