I eventually found references to the code below after twawling through the forums and the web, and this seems to have done the trick (add to functions.php). This is apparently caused by a lack of support for custom post types in feeds (hopefully something that will be worked on in the future).
function feed_request($qv){
if(isset($qv['feed']) && !isset($qv['post_type']))
$qv['post_type'] = array('news', 'tla');
return $qv;
}
add_filter('request', 'feed_request');
Now, viewing the feed should be as simple as typing ‘https://yourdomain.com/feed – in the example above you will see only posts of type ‘news’ and ‘tla’. If you want a secondary feed, for your job vaciencies for example, you could override the code above like this – ‘https://yourdomain.com/feed/?post_type=career’
Or, if you simply want to add every post type that you have to the main feed.
function feed_request($qv){
if(isset($qv['feed']))
$qv['post_type'] = array();
$qv['post_type'] = array('public' => true, '_builtin' => false);
return $qv;
}
add_filter('request', 'feed_request');
Any way, this caused me some hassle, so I hope this post is of use to people in the future.