[Mike]

There's 3 or 4 different audio tracks for those idents; The first has the hold at the end, the second has a short cut, the other is more orchestral and the final one is a christmas ident (I'd assume as it says '6/+bells' on the notes). They're not labelled up for any particular use by the composers.

It's worth noting as well they were all composed/arranged/performed and produced together alongside Thames News and Thames Weather, nothing seems to have 'come later' - so probably just a stylistic choice.

All 4 can be heard here (n.b. the hiss is added by me and the quality greatly reduced to prevent pres-snatching YouTubers uploading it).