anchor.diff:            <th class="selectable-row">
               <div class="relative">
                 <label>
  -                <input type="checkbox" />
  +                <input type="checkbox" class="js-toggle-all" />
                 </label>
               </div>
             </th>
  
positive.code:     </tbody>
      </table>
  
      <script>GOVUK.Mappings.setupTables()</script>
    </ul>
  </div>
  <hr>
  
negative.code:         <td class="selectable-row">
            <div class="relative">
              <label>
                <input type="checkbox" checked="checked" class="js-toggle-row" />
              </label>
            </div>
          </td>
  