anchor.diff:      const colour = event.colour;
       const predicted = event.predicted;
       counts[colour] += 1;
  -    counts.lastEvent = event;
       // Don't count timed_out or faulty as incorrect predictions.
       if (predicted && predicted != 'none' && isRag(colour)) {
         if (colour === predicted) {
  
positive.code:   const totalCount = () => {
      const total = counts.red + counts.amber + counts.green + counts.timed_out;
      return $('<div>', {
        'class': `traffic-light-count ${lastEventColour()}`,
        'data-tip': 'traffic_light_count',
        'data-red-count': counts.red,
        'data-amber-count': counts.amber,
  
negative.code:       id:'miss-img',
        src:'/traffic-light/image/circle-miss.png'
      });
      const light = lastLight();
      const missColour = predictedIncorrectly(light) ? light.predicted : '';
      const $missCount = $('<div>', {
        id:'miss-count',
        class:`traffic-light-count ${missColour}`
  