By John Oxley Election battle buses traversing the country and photo ops in factories showcase the beauty of Britain in all its infinite variety, say John Oxley It sometimes feels like British politics never really extends beyond the circulation zone of this newspaper. The Cities of Westminster and London constituency forms the nexus between business and political power, the hub of intrigue and the heart of lobbying. Today, however, it is just one of 650 seats up for grabs and the general election should be a great reminder of the variety and challenges of our national politics. It has been re…