CI - drilling to a single post/thread - php

Question

Could someone please enlighten me as to what I'm doing incorrectly - I'm currently following a net tuts+ video, which goes through the process of listing an array of posts, and then having the ability to click on one post, to be shown the detail.
I'm adapting the above method for my own solution/web application, but I'm at a loss as to why my array is blank.
I'm using this line to create link/anchor to the next controller
<a href="<?php echo base_url(); ?>Search/site/<?php echo $site->siteID; ?>"><?php echo $site->site_title; ?>
I've highlighted the code where I believe I'm going a miss,
Thanks
Controller
class Search extends CI_Controller {
public function display($sort_by = 'site_title', $sort_order = 'asc', $offset = 0)
{
$limit = 20;
$data['columns'] = array(
'site_title' => 'Site Name',
'site_uprn' => 'Unique Property Reference'
);
$this->load->model('search_model');
$results = $this->search_model->search_sites($limit, $offset, $sort_by, $sort_order);
$data['sites'] = $results['rows'];
$data['num_results'] = $results['num_rows'];
//pagination
$this->load->library('pagination');
$config = array ();
$config['base_url'] = site_url("Search/display/$sort_by/$sort_order");
$config['total_rows'] = $data['num_results'];
$config['per_page'] = $limit;
$config['uri_segment'] = 5;
$this->pagination->initialize($config);
$data['pagination'] = $this->pagination->create_links();
$data['sort_by'] = $sort_by;
$data['sort_order'] = $sort_order;
$this->load->view('search', $data);
}
**function site($siteID){
$this->load->model('search_model');
$data['site_detail']=$this->search_model->site_detail($siteID);
//$this->load->view('site', $data);
}
}**
Model
<?php
class Search_model extends CI_Model {
function search_sites($limit, $offset, $sort_by, $sort_order){
$sort_order = ($sort_order == 'desc') ? 'desc' : 'asc';
$sort_columns = array('site_title', 'site_uprn');
$sort_by = (in_array($sort_by, $sort_columns)) ? $sort_by : 'site_title';
//site table
$q = $this->db->select('siteID, site_title, site_uprn')
->from('sites')
->limit($limit, $offset)
->order_by($sort_by, $sort_order);
$ret['rows'] = $q->get()->result();
//count query
$q = $this->db->select('COUNT(*) as count', FALSE)
->from('sites');
$tmp = $q->get()->result();
$ret['num_rows'] = $tmp[0]->count;
return $ret;
}
**//sites details
function site_detail($siteID){
$this->db->select()->from('sites')->where('siteID', $siteID);
$query = $this->db->get();
return $query->first_row('array');
}
}**
View
<div id="right">
<h5>Site Details</h5>
<ul>
<li><?php $site_detail['siteID']?></li>
<li><?php $site_detail['site_title']?></li>
</div>