Thanks, yes I usually do use Kodi's addon for tvheadend. Playing them direct from the folder is simply a way to check that the basic underlying data is there and correct. But I think MrMC doesn't allow addons, so that doesn't help?
TV Headend only - by default - uses the broadcast metadata sent via DVB-T/T2 - so if the broadcaster doesn't add episodes numbers, they aren't there (or are just part of the synopsis) Similarly programmes with "NEW :" added to their title can be an issue.
Indeed and the way some channels add New, then remove it, then add it back again is an irritation. But tvheadends regex searching can help there.