create url with destination parameter and additional query string to views page with exposed filters
Instead of Trying to generate destination manually, can use drupal_get_destination(). So your above code would be like this:

$url = url('admin/dashboard/applications/create/' . $row-&gt;nid, array('query' =&gt; drupal_get_destination()));
$link = '&lt;a class="create-app" href="' . $url . '" title="Create application"&gt;App+&lt;/a&gt;';


drupal_get_destination() gets the current path + encode the query strings and make them as destination. this will generate below URL:

http://www.site.com/admin/dashboard/applications/create/154575?destination=admin/dashboard/enquiries%3Fnid%3D%26field_enquiry_fname_value%3D%26field_enquiry_email_value%3D%26field_enquiry_country_tid%3D%26field_enquiry_campaign_id_value%3D%26field_enquiry_emailed_value%3D0%26field_enquiry_stage_1_tid%3DAll%26field_enquiry_enabled_value%3D1


instead of your URL.

http://www.site.com/admin/dashboard/applications/create/154575?destination=admin/dashboard/enquiries%26nid%3D%26field_enquiry_fname_value%3D%26field_enquiry_email_value%3D%26field_enquiry_country_tid%3D%26field_enquiry_campaign_id_value%3D%26field_enquiry_emailed_value%3D0%26field_enquiry_stage_1_tid%3DAll%26field_enquiry_enabled_value%3D1


The difference is the encode of '?'. I have tested it in  local D7 installation.