php - cakephp - how to structure this query

I'm using cakephp 2.3 and trying to paginate a query which retrieves all my 'jobs' within a certain mile radius. Luckily I found the query I think I need, but I'm having problems getting it to get the right data.

EDIT
So each 'job' record has a lat and lng field and another user performs a search by entering their own lat and lng values as well as a mile radius in a search form. In the code below the php variables $lat $lng and $miles in my paginator below are the user entered search parameters.

The query, which I found here https://developers.google.com/maps/articles/phpsqlsearch_v3?hl=el-GR - should look like:

    SELECT id, 
           ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin( radians( lat ) ) ) ) AS distance 
      FROM markers 
    HAVING distance < 25 
  ORDER BY distance LIMIT 0 , 20;

and I've got that going through my paginate like so:

$this->Paginator->settings = array(
                                'fields'=>array('id','( 3959 * acos( cos( radians(37) ) * cos(radians( '.$lat.' ) ) * cos( radians( '.$lng.' ) - radians(-122) ) + sin( radians(37) ) * sin(radians( '.$lat.' ) ) ) ) AS distance '),
                                'limit' => 20,
                                'group'=>'distance having distance < '.$miles
                                        );
$jobs = $this->Paginator->paginate('Job');

and the sql that produces looks like:

SELECT `Job`.`id`, ( 3959 * acos( cos( radians(37) ) * cos(radians( 54.59728500000001 ) ) * cos( radians( -5.930119999999988 ) - radians(-122) ) + sin( radians(37) ) * sin(radians( 54.59728500000001 ) ) ) ) AS distance FROM `trainnation`.`jobs` AS `Job` LEFT JOIN `trainnation`.`users` AS `User` ON (`Job`.`user_id` = `User`.`id`) LEFT JOIN `trainnation`.`courses` AS `Course` ON (`Job`.`course_id` = `Course`.`id`) WHERE 1 = 1 GROUP BY distance having distance < 100 LIMIT 20

which looks right to me but doesn't pull any info at all. There should be at least 9 records which are well within 100 miles of that location but $jobs is always empty.

Can anyone spot what I'm doing wrong?