[Dumyat]

Ok, so it doesn't use Genre IDs at all you need to use some kind of genre text mappings. There is one implemented for Rytec which assumes the the genre text is in between square brackets. 
In the above snippet you will see the first 3 items all map to targetId 0x10 (which is the kodi genre Movie/Drama), this is the ID that kodi understands. If the addon finds the text "General Movie/Drama" or "Film" or "Animated Movie/Drama" they will all get mapped to this ID. Make sense?
 

Yeah, I think what was maybe confusing me was the theme file from the Radiotimes plugin has a GenreID for each of these new genres and since they didn't appear on my STB or in Kodi inside square brackets, I just assumed (incorrectly as it turned out), that I was probably taking the right approach  
Using the above example, the movie genres I mentioned previously should now be configured something like this:- 

php:
<mapping targetId="0x10">Movie</mapping> <!-- 0x10 Movie/Drama -->

<mapping targetId="0x10">Movie - Drama</mapping> <!-- 0x10 Movie/Drama -->

<mapping targetId="0x11">Movie - Thriller</mapping> <!-- 0x11 Detective/Thriller -->

<mapping targetId="0x12">Movie - Action</mapping> <!-- 0x12 Adventure/Western/War -->

So would that mean the genre 'Movie - Thriller' would appear in the genre field in Kodi like this, or would it appear as 'Detective/Thriller'?
You can find all the new text based genres for the <e2eventdescription> value on the 'theme file' I included on the previous link. Just open in notepad and you will see them all. This is how they are now appearing in Kodi before the main programme description. 

What's really nice is they are very specific for each programme. Also, each genre group seems to include a main genre heading like Movie, Entertainment, Music, New & Documentaries, etc. Ideally, it would great if we could show the main genre heading in the genre field, then the more specific genre to be shown as part of the description like I'm seeing currently.
I'm not sure the DVB genre standards that Kodi uses actually give enough scope to achieve this though.
Let me know if you need anything else.