gistfile1.txt

add_action( "propertyhive_property_imported_blm", "set_exempt_custom_field", 10, 2 );
function set_exempt_custom_field($post_id, $property)
{
    if ( isset($property['COUNCIL_TAX_EXEMPT']) && $property['COUNCIL_TAX_EXEMPT'] == '1' )
    {
        update_post_meta( $post_id, '_council_tax_exempt', 'Yes' );
    }
    else
    {
        update_post_meta( $post_id, '_council_tax_exempt', 'No' );
    }
}