Denis Wirth-Miller and Dicky Chopping were a couple at the heart of the mid-twentieth century art world, with the visitors' book of the Essex townhouse they shared from 1945 until 2008 painting them as Zeligs of British society. The names recorded inside make up an astonishing supporting cast - from Francis Bacon to Lucian Freud to Randolph Churchill to John Minton. Successful artists, although not household names themselves, writing Dicky and Denis...