LONDON.- There is Paul Cole. An American tourist who happened to be on vacation in London in August 1969. You might find him familiar somehow. As he walked around the streets of St John’s Wood waiting for his wife that day, he stumbled across four guys being photographed on a zebra crossing. He watched for a while as they went there and back again. And again. And again. That’s how he was captured for posterity on one of the most famous photographs of all time – the the cover of the Beatles’ Abbey Road LP, standing to the left of John Lennon’s head on the album sleeve. But, as a new exhibition reveals, he might so easily not have been on the cover. ‘Beatles and Bystanders: the unknowns at Abbey Road’ on show at Snap Galleries’ Piccadilly space in central London, uncovers, for the first time, at least a dozen other characters who might equally have featured on the cover of one of the most