csv_from_result only returning column labels

I'm looking to use CSV from result to produce a CSV file from a query; my code is like this;

PHP Code:

                   $delimiter = ",";
                    $newline = "\r\n";
                    $enclosure = '"';
                    $data = $this->dbutil->csv_from_result($query, $delimiter, $newline, $enclosure);
                    force_download($fileLabel.'.csv', $data); 


and only returns the following

Code:

"learnerID","NameFirst","NameLast","MobileNumber"

Which is the column labels when I know the results do have entries (as is shown in this vardump of the $query put though the result_array)

Code:

array (size=3)
 0 =>
   array (size=4)
     'learnerID' => string '17' (length=2)
     'NameFirst' => string 'Test' (length=4)
     'NameLast' => string 'Case' (length=4)
     'MobileNumber' => string '7000000000' (length=10)
 1 =>
   array (size=4)
     'learnerID' => string '18' (length=2)
     'NameFirst' => string 'Case' (length=4)
     'NameLast' => string 'Test' (length=4)
     'MobileNumber' => string '7000000000' (length=10)
 2 =>
   array (size=4)
     'learnerID' => string '19' (length=2)
     'NameFirst' => string 'a' (length=1)
     'NameLast' => string 'b' (length=1)
     'MobileNumber' => string 'c' (length=1)

What am I doing wrong?