episode missing and don't know where to put it

Why? The episodes have to be in the original release order. So, just find out when it first aired and add it where it should be. Unless you have reasons to believe it was a special?

The seasons on TVDB and TMDB do not match what UK broadcasters, Wikipedia & IMDB uses.

Series 3 thru 26 need deleted so someone can create these correctly.

@Jameseh said: Series 3 thru 26 need deleted so someone can create these correctly.

@banana_girl said figure out when all of the episodes originally aired and rebuild. What source shows the airfare? Can I these seasons be deleted and rebuilt?

I'm happy to do it but I'd want confirmation from a mod that the existing seasons based on years will be deleted before I spend a few hours doing so.

Just a few thoughts from me:

Before doing anything, we should clarify and decide how to sort all of these episodes in general here on TMDb?
The current order here on TMDb is a mix-up of calendar years and production seasons - it should be updated.
It should be either in calendar years - or in production seasons - or without any seasons at all?

1.) As far as I can see, the official website currently on Channel 4 does not use any seasons:
https://www.channel4.com/programmes/unreported-world/

I don't see any calendar years and production seasons - it's all a continous line of episodes ordered by air date.
The current list of episodes goes only back to 2011 - not to the year 2000.
I assume it's the order of all episodes currently available for streaming, which means available at this certain point of time.

2.) The official YouTube channel of the show actually provides a distinction in playlists:
https://www.youtube.com/@unreportedworld/playlists

The titles of the playlists are a bit confusing - but do you see the playlists titled "Spring 20XX" and "Autumn 20XX"?
As far as I could figure this out, these are seasons (or in British "series") of production cycles.
And these production seasons/series are actually used for series denominations by crew members and in public announcements.

Just for 1 example that I found, take this press release from Channel 4 from March 2011:
https://benjaminhuguet.com/portfolio/channel-4-unreported-world-shorts

Quote:
"This change will apply to the 21st series - this new ten-part run will begin on Friday March 25th"

So, it officially states the 21st series starts on March 25th 2011.
When you take a look at all the air dates of the episodes, this means it's the official count of the production cycles of spring and autumn per each calendar year:

1. Autumn 2000 (no production/broadcast in spring )
   
2. Autumn 2001 (no production/broadcast in spring)
   
3. Spring 2002 (broadcast in winter and 1 episode in July)
   
4. Autumn 2002
   
5. Spring 2003 (broadcast in winter/early spring)
   
6. Autumn 2003
   
7. Spring 2004
   
8. Autumn 2004
   
9. Spring 2005
   
10. Autumn 2005
    
11. Spring 2006
    
12. Autumn 2006
    
13. Spring 2007
    
14. Autumn 2007
    
15. Spring 2008
    
16. Autumn 2008
    
17. Spring 2009
    
18. Autumn 2009
    
19. Spring 2010
    
20. Autumn 2010
    21. Spring 2011 (starting March 25th, 2011)
    

When you count the seasons like this, you'll end up with the sorting that you can see on IMDb right now:
https://www.imdb.com/title/tt0477545/episodes/?season=47&ref_=ttep

Should we use this order here on TMDb?
The playlists on the official YouTube channel are incomplete, but they certainly follow this order.
So that's indeed an official order based on the production of this show.

3.) The order on TVDb is per calendar year (starting with 2000 = season 1), the same way the order here on TMDb is done right now at the start:
https://www.thetvdb.com/series/unreported-world#seasons

This is - obviously - an arbitrary order, because it does not reflect any official order from the network.
And the rules for TMDb state:
"Our main goal is to reproduce the seasons exactly as they first aired on the original network."
https://www.themoviedb.org/bible/tv/59f73eb49251416e71000026

Conclusion:

In my opinion, the current order based on calendar year here on TMDb is wrong, because it's against the main rule.
But we sometimes make exceptions to the rule - I'm not sure we should make an exception for this show.

We could use the production order that is used officially in press releases and by crew/production members.
I wouldn't object to this - it would follow our main rule.

My prefered solution would be to put all episodes into 1 single season.
And then we could use episode groups for production order and order by calendar year.
But that's a lot of work to do.