What I actually ended up with 

<script type="text/javascript" src="/js/jquery-1.3.2.min.js"></script>
<script type="text/javascript" src="/js/jquery.bgiframe.pack.js"></script>
<script type="text/javascript" src="/js/jquery.autocomplete.js"></script>
<script type="text/javascript">
  $(document).ready(function(){

    $("form.enrol-form input#house").autocomplete(
      '/js-ac/anon/residential-address',
      {
        width:300,
        requestType:'POST',
        dataType:'json',
        minTest:function(str) {
          if(str.match(/\S\s+\S\S\S/) || str.length > 6) return true;
          return false;
        },
        matchSubset:false,
        matchContains:false,
        highlight: false,
        scrollHeight:220,
        scroll:true,
        max:100,
        cacheLength:1,
        autoFill:false
      }
    ).result(function(event, rec) {
      $("form.enrol-form input#house").val(rec.house_number);
      $("form.enrol-form input#street_name").val(rec.street_name);
      $("form.enrol-form input#town_suburb_name").val(rec.town_city);
      $("form.enrol-form input#town_suburb_name").focus();
    });

  });
</script>
<link rel="stylesheet" type="text/css" href="/style/jquery.autocomplete.css">