In 1990 a young Welshman called David Dawson was taken to Lucian Freud’s house by his employer, the art dealer James Kirkman. ‘After that first meeting,’ Dawson recalls, Freud would ‘phone me every morning. A couple of weeks later he invited me round again.’ Kirkman’s assistant was to repeat his visit every day for the next six years. It was only in 1996 that Freud finally popped the question. ‘He asked me to sit for a painting,’ Dawson says in his new book, A Painter’s Progress.