meta query not showing any results?

Question

you’re missing an array within the meta_query element:

$args = array(
           'post_type' => 'programmes',
           'meta_query' => array(
                              array(
                                   'key'     => 'linktovideocatchup',
                                   'value'   => '',
                                   'compare' => 'NOT LIKE'
                                   )
                              )
            );

(this is required to allow for querying of multiple meta fields.)

you also had an extraneous comma after the meta_query array element which can cause problems.

i think you should also be able to use the operator ‘<>’ rather than ‘NOT LIKE’, i believe it’s more efficient.

there’s a good write-up on the meta_query functionality here: http://scribu.net/wordpress/advanced-metadata-queries.html