With an 80s update of Van Eyck’s Arnolfini Betrothal on the cover (him: beret and baggy trousers; her: turquoise jersey turtleneck dress, Michelle Fowler from EastEnders ‘do and stripy tights), the Observer’s investigation into the state of contraception on 20 January 1985 offered the possibility there might be a new phase of sexual liberation in keeping with the times just around the corner.