John Oxley is a consultant, writer, and broadcaster. His SubStack is Joxley Writes. The death of Penelope Keith is the passing of a much-loved national treasure. As a Conservative, it also means the loss of perhaps one of our most famous fictional members. Margo Leadbetter was canonically a staunch Tory, and to many embodied the spirit of the party. She was the comfortably off wife of a Surrey executive, deeply enmeshed in local life, fastidious…